YMMV / Bridge

• Broken Base: In tournament/club play, whether scoring is better at match points or international match points (usually called IMPs). Match points merely compare scores between similarly-facing partnerships - the team that scores better gets a match point (even if they only did better by 10 points), and ties award half a point. IMPs compare the scores between the teams and award more points to teams on a roughly logarithmic scale. Which is better can rouse fierce debate - fans of the former argue that IMPs can unfairly swing things on a single large-scoring hand (such as a slam or a doubled contract), while proponents of the latter criticize match points for hair-splitting over a single overtrick or playing in no-trump versus a major suit (assuming the same bonuses and number of tricks taken, the no-trump contract will earn exactly 10 points more than the major suit contract - which could be a huge swing in match points but is worth no IMPs).
• That One Rule: In tournament and club play, there are procedures for dealing with a board that cannot be scored for any reason at one or more tables. These are mathematically complex, and can result in a pair not involved having its score reduced — for example, a pair that might otherwise have gotten 10 out of 10 on that board will now get only 9.9. This is disliked both by new players (who don't understand the calculations involved) and by experts (for whom that small adjustment can have an impact on their placement).
  • The scoring procedures for a fouled board (where cards got moved between hands somehow, so that not everyone played exactly the same hand) are even more complicated; fortunately, this comes up very rarely.
  • The rules for a revoke (playing a card of a suit other than the first suit led when following suit is possible) are a bit baroque and have resulted in numerous appeals at clubs and events. The rules state that up to two penalty tricks may be awarded to the aggrieved side - one for the trick where the revoke happened, and one for the trick when the revoke card (the one that should have been played on the revoke trick) finally gets played. However, this is only supposed to apply when both the aggrieved partnership lost both tricks in question and it's deemed that they would have won the tricks in question if play had progressed properly (for example, if the aggrieved side would have won the revoke trick regardless, they wouldn't be eligible to receive a penalty trick for that trick). Arguments about how play would have progressed differently can result in much hair-splitting over penalty tricks rewarded, and that's even before getting into the issue of how many people (including directors, at clubs and tournaments) argue that there should be a two-trick penalty regardless. Some players will just Hand Wave the two-trick penalty rule as being hard-and-fast just due to not wanting to deal with hashing out how things should have gone.