What is the most annoying thing that can happen to you in chess?

Check sequence without repetition followed by pawn or king move followed by check sequence without repetition cycle on rinse and repeat. This is something I commonly do in Queen and 5 pawns vs rook and 3 pawns scenarios, especially in timed settings to drain clock time. I did this in a tournament once in Sydney, Australia and the entire room could hear the loud sound of "Check!", some even thought it was a draw but it wasn't. That ended with me having my original 45 minutes I started with on my clock vs only 1 minute of time on his clock.

I even used this technique against a 1600 rated advanced computer in a non-timed setting and won in 181 moves !
What is the most annoying thing that can happen to you in chess? Is it stalemate, losing your queen, losing in itself, or your internet connection failing? Just wondering.