or having an opponent who takes so long to do there turn
What's the most annoying thing in chess?

Tilting. The Elo points matter more than a win or lose. Like they are bragging rights. Losing points is worse than hanging mate. What a blow to the ego.

I find it annoying when I finally get an advantage and my opponent resignes. I've heard other people say they prefer it that way, but I enjoy checkmating.

Having an enemy who Instantly uses the Bishop of queen to go to the left or right side of the middle of the board i think that's a cheap move