Eat your lunch, but then realize that your time is out and you lost the game
Worst Thing To Do On Your First Move

Scream so loud you became deaf then you observed someone else’s game. Your time ticked you didn’t here and lost on time.

1. e4 f5 -- the Fred Defense. Worst thing to do as Black on first move. https://www.youtube.com/watch?v=_3YhSuHchAg
For me the worst thing I can do on the first move is to make the first move, since it guarantees a loss.