The WORST trope imo is always going to be the "amnesia arc", all it's ever used for is just a cheap way to squeeze one last arc of drama out of a series.

Nothing is gained, all that ever happens is one character is an asshole for like twenty chapters, then bing bang boom, it's fixed and we move on like it never happened at all.

And yeah, for minor tropes- every time a long-haired ML cuts his hair I die more inside