Instead of demanding that Linus return his dream diary the next school day, why didn't Max think of telling Mr. Electricidad or the principal about the theft so Linus would have been forced to give him back his diary the same day he took it from him? If Max had done that, then Linus wouldn't have possibly gotten any chance to vandalize it. Most of the time, when one child steals something from somebody at school, they are immediately reported.
Why doesn't Mr. Electricidad allow Max to befriend his daughter Marissa at first if he had previously encouraged him to make friends? His daughter seems to have no friends at all and by asking Max to not befriend her, he looks like a major hypocrite and a bad parent who wants his daughter to be friendless. By the way, why does he place his daughter under the class' vent?
Why does Lavagirl tell Max that blue glasses are for boys and pink glasses are for girls aboard the rocket if she was handing him a pair of pink glasses? It seems like she is mocking Max by not giving him a blue pair?
Why didn't Lavagirl tell Max and Sharkboy that the Crystal Heart could only be used by the Ice Princess? She could have said something like "Hey guys, I know you want to see this Ice Princess I hate because her powers are the opposite to my powers, but the Crystal Heart only works if she uses it, so let's not bother into going to her place and ask her for it". That said, why didn't the Ice Guardian nor the Ice Princess themselves tell them that the Crystal Heart didn't work if Max used it?
At the end, are Sharkboy and Lavagirl real or not? The film's message is that you must solve your problems in the real world instead of doing it in a fantasy one, but there are certain moments in the film which put into question whether Sharkboy and Lavagirl are actually real or not. Like the instance in which the cookies are burned or with shark bites? Granted, Max could have burned them, but he has no pointed teeth, so his parents should have known that their son wasn't the one who ate the cookies. And if they aren't real, then who saved Max's parents during the tornado scene? That said, was the final battle against Mr. Electric and Marissa's powers real or not? The whole class saw the ordeal!
