As someone with social anxiety, I feel very natural writing characters who can't confess to a crush, haha. That said, I can see how it would be annoying when there's no obvious reason for the character to be anxious about it.
As for tropes I hate, I feel like I don't care too much to be honest? Like OP said, it really depends on how they're used. As a kid, though, I remember I liked to make fun of the "turn your back on your opponent because you think they're dead, but oops they're actually not dead!" trope a lot.
(Ways you could use the trope effectively: to show a character's inexperience, maybe a more experienced character could call them out for it)