Pet peeve: stories that hinge on stupidity.
Romeo and Juliet is a good example of this kind of thing. All the problems, all the escalations, are based on characters doing stupid things for no good reason. People feud, get into fights, and kill themselves, because they can't just sit down and think for five minutes.
"The characters do something stupid" is a really lame way to kick it up a notch. Horror movies, sitcoms, (I can't stand Seinfield, because it's really bad about this.) all do it, and it's really, really annoying, because it's usually totally transparent. It's either out of character, or the character is built around doing stupid stuff in the first place.
Sure, if it's grounded in the character, it can work. People have flaws; that's interesting. But not if those flaws are "impulsive" or "poor judgment" or "prone to stupidity." That's just writerly laziness.
There are other ways to drive the action. Get yourself a good antagonist, give your characters interesting flaws, make fate really mean. Anything. Just don't make them prone to random stupidity at inconvenient moments.