The most annoying things in gacha to me are :
Wrong use of speech bubbles (example, when someone is thinking but it has a shouting speech bubble)
Not changing the face (such as when a character doesn't change their expression the entire time)
The generic-sound-loop music or having bad music until the very end
Gacha Studio
Only using very few different poses the entire time (it makes it seem stiff)
Cliffhangers.
When people use a word that they don't even know what it means
JD2005 :-(
lunamoonlight well, the last one is fine most of the time, i do that last one a lot, but if the whole video is centered around that word, no.
KnightStar I agree!!