History DidntSeeThatComing / RealLife

** Hurricane Harvey in 2017 decided to park its butt in Western Texas, drowning the Houston area in up to ''40 inches of rain''. The National Weather Service's precipitation scale didn't go that high until this incident.

* In 2018, Creator/ActivisionBlizzard thought it would be a good idea to announce ''VideoGame/DiabloImmortal'', a [[MobilePhoneGame mobile game]] as TheClimax to that year's [=BlizzCon=] convention after building up hype for a new ''VideoGame/{{Diablo}}'' game for several months beforehand. [=BlizzCon=] is attended by [[Creator/BlizzardEntertainment Blizzard]]'s most dedicated fans [[DidntThinkThisThrough who are all but entirely comprised of]] [[UsefulNotes/IBMPersonalComputer PC]] [[DidntThinkThisThrough gamers]], who had paid $200 a pop in hopes of seeing a mainline ''Diablo'' game, especially since the then-latest game in the franchise, ''VideoGame/DiabloIII'', had been released over six years ago at the time; so the announcement went down about as well as you can imagine. One attendee (in)famously asked if ''Diablo Immortal'' is "an out-of-season April Fool's joke". Somehow, Blizzard hosts did not expect a negative reception of this scale to a mobile game being announced as the grand finale to a PC-centric convention, as demonstrated by announcer Wyatt Cheng's reaction to the crowd ''booing'' the confirmation that, at the time, there were no plans for a PC port[[note]]This was the first time in [=BlizzCon=] history that a game announcement was booed[[/note]]; he was so surprised that he impulsively asked the crowd, "Do you guys not have phones?", which also went down about as well as you can imagine.

* Overlapping with Unknown Knowns and False Assumption, the sinking of the ''[[UsefulNotes/RMSTitanic Titanic]]'' has this trope written all over it.

* During UsefulNotes/WorldWarI, the Austro-Hungarian battleship ''[[http://en.wikipedia.org/wiki/SMS_Szent_István SMS (Seiner Majestät Schiff) Szent István]]'', [[GeniusBonus which translates as "His Majesty's Ship Saint Stephen"]], was torpedoed and sunk by two Italian motor torpedo boats that ''just happened to pass in the area''. This goes under the Unknown Knowns category, as the Austro-Hungarians knew that the Italians used motor torpedo boats and considered them a threat due to their tendency to attack their fleet in the harbours. They just didn't expect them to be able to torpedo a battleship in the middle of the sea in spite of a destroyer and torpedo boat screen (and in fact thought it had been submarines until the Italians started bragging).

** In 1916 the Italians were completely caught by surprise by the Austro-Hungarians attacking: doing some math they had figured the enemy didn't have the manpower to fight Russia on one front and mount an offensive on the other, and the Austro-Hungarian nearly broke through. Then the Austro-Hungarians were caught on the receiving end of this: the Russians attacked en-masse, forcing them to move all the attacking troops on the other side of the country. Both fall into Unknowns Known: the Italians had noticed the massing of troops but dismissed it, and the Austrians should have seen the Russian attacking that fast.

** The Battle of Caporetto contained a few of these. First, the Austro-Hungarians and Germans broke through due to the Unknown Known of the new German tactics and the False Assumption gas didn't work in high mountain, helping the breakthrough. Then the Austro-Hungarians ran into the Unknowns Unknown of the ''multiple'' reserve defensive lines that Cadorna and some of his subordinates had passed the previous year predisposing just in case: while a ModernMajorGeneral wasted an artillery trap that could have annihilated a prong of the assault and the Italians (whose army had almost completely dissolved under the pressure of the enemy attack and the low morale, with many soldiers deciding they would just return home) didn't get to the Tagliamento river in time to stop the enemy, by the Piave river the Italian soldiers had decided that the invader was to be defeated, reformed the army and held the line, and on the north the Austro-Hungarians discovered that a good chunk of the immense Italian artillery park had been placed on a mountain they couldn't cut off from supplies.
** 1918 has the Battle of Vittorio Veneto, a massive case False Assumption. By that point, everyone had figured that the Allies would win the war, and the plan was for Austria to negotiate peace and Germany to fight through the winter to get better peace conditions. Then the Italians surprised everyone (including their own allies) by launching a sudden and massive offensive that they weren't supposed to have the morale and will for. Thanks to this and the Italian artillery being brought up to eleven, when the Italians were finished the Austro-Hungarian army had been ''annihilated'' as a coherent force and was running, the Austro-Hungarian Empire had barely managed to surrender unconditionally before collapsing, and Germany had to beg for peace before the Italians marched through Austria to attack them from the south.
** Finally, the very last of the war: by the time the armistice on the Italian front took effect and the Austro-Hungarian Empire had started collapsing, [[{{Determinator}} the Austro-Hungarian Army had]] ''[[{{Determinator}} reformed as a coherent fighting force]]''. This falls under False Assumptions, as everybody had assumed that no army could do this... In spite of the Italian Army doing almost the very same thing exactly a year before. The Italian high command was very happy that the armistice had taken effect as the Austro-Hungarian Army proved they had outlasted the empire they served and laid down their arms (not surrendered) a ''regiment or division at time''.
** Italians kept doing this long after UsefulNotes/WorldWarII. Italian Navy's special ops were responsible for wrecking two British battleships, the HMS ''Valiant'' and HMS ''Queen Elizabeth'' in 1941, in the middle of Alexandria harbor and seriously weakening the strength of the Royal Navy in the Mediterranean for more than a year. So common were such activities that, when the Soviet warship ''Novorossyisk'' (formerly Italian battleship ''Giulio Cesare'', taken over by the Russians after UsefulNotes/WorldWarII) blew up at Sevastopol in 1956, Russians suspected that the Italians might have pulled it off as a sort of revenge, although no firm evidence of this ever emerged.

** The collapse of the towers completely baffled architects and engineers. At the time, no skyscraper had ever collapsed due to a fire. Regarding the aforementioned plane crash scenario, it was expected that there would be a terrible fire but the structure would still stand. In 1945, a B-25 had hit the Empire State Building, which survived the impact.

* The Battle of Midway: The Japanese did not see losing the battle coming. Not only were they not expecting an aggressive YS Navy, they were not expecting them to show up so soon. Not only did US codebreakers crack their ‘unbreakable’ code and know when the attack was coming there were three US carriers present when the Japanese expected only two. Japanese leaders were blindsided when in minutes US dive bombers knocked out three of their carriers in less then 10 minutes.
* The Guadalcanal Campaign: the Japanese were completely caught off guard when seemingly out of nowhere US Marines attacked and seized the airfield they were building on the island of Guadalcanal. This lead to a massive campaign on both side to either hold the airfield or try to take it back.
** The US does not get off scott free on this as, more than once, during night actions they were blindsided by attacks from Japanese task forces trying to force the seas to land more troops to take back the island or to bombard Henderson Field so their army can retake the base. Of course this wasn’t one sided as US task groups also managed to do the same as well. The area is now called Iron Bottom Sound now for a very good reason.

* Part of the reason why the 1929 Great Depression and the 2007 Great Recession were so devastating was the fact that they happened due to things that were seen as inevitable in hindsight, yet almost nobody - certainly nobody in any position of power - saw coming. In the 1930s the world economy was wrecked among other things due to the fact that many companies had refinanced long-term investments with short-term loans. [[WhatCouldPossiblyGoWrong What could possibly go wrong with that?]] The crisis was exacerbated when a major bank collapsed in Austria and no government saw a need to bail them out ("too big to fail" was not a common term back then), which led to a run on the banks and the collapse of any domestic European credit market, after American banks already started calling back their credits to European debtors. In 2007 the thing nobody saw coming was that housing prices could ever go down in a country with a growing population. Ultimately the whole house of cards that was built on the assumption of perpetually growing prices in the housing market came tumbling down, taking the US economy and shortly thereafter the European economy with it.

* The firing of James Comey from his position as head of the FBI turned into this for the Trump administration where under the False Assumptions that the Democrats would cheer on Trump for getting rid of a guy they hated instead had them point out just how suspicious the entire action was, and ultimately caused a lot of backlash. Comey, for his part, didn't see his firing coming and learned about it when he saw a report on TV about it, which he initially thought was a prank.

* The 2022 US Midterms was one of the worst showings for the Republicans with the party barely winning the House of Representatives and failing to retake the Senate when, traditionally, the minority party would have gained numerous seats. Many GOP nominees had gambled on tried-and-true sticking points like the economy, crime and border safety. Instead, their talking points were overshadowed by the loss of abortion rights and fears of democratic backsliding with the Dobbs Decision and the Capitol Insurrection still in the public conscience. At the same time, they overlooked high turnout among Democrat-leaning Millennial and Generation Z voters, who were excited by popular Democratic policies and turned off by GOP hostility to abortion and democracy. After over a month of counting, the Republicans lost a seat in the Senate and narrowly won control of the House of Representatives but only by 9 votes instead to the dozens they expected.

* The submarine USS ''San Francisco'' once ran full speed into an [[http://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)#Collision_with_seamount Underwater MOUNTAIN.]] Apparently, the captain and crew should have seen that coming if they were doing their jobs right (the captain ended up relieved of duty and six other crewmen were reprimanded and reduced in rank). So that would make this a case of unknown knowns.

** Technically untrue with regards to the intelligence services. It wasn't so much that 9/11 was unexpected, at least by counter-terrorism professionals - between them, the CIA and FBI had enough intel to sweep the attackers up, but for "the Wall", a bureaucratic device that limited cooperation between the two agencies - Mohammed Atta even put the actual name of his hotel on his landing card! It is just that the attack happened before people expected it to, so more a case of '''Known Unknown.''' Of course, the US ''public'' was totally blindsided.