most ANNOYING thing while reading a good manhwa that makes u drop it

default is anything gross like rape, incest, pedophilia etc.
i'll go first. when a harem is introduced in the middle of an action story, when a character is said to be the best and the scariest but immediately becomes a dainty little thing who can't fend for her/himself when the love interest shows up, random amnesia or accident arc which isn't even necessary for the plot to move forward.
now your turn