What causes people to have a bad game?

Hey that's the same thin that happens to me. I have a bad game I suck but when I have a normal/good game, I'm awesome!

This is mostly a mental area. Your game prep is a big deal, especially in higher level games. You need to be well rested, well hydrated, and relaxed as much as possible. Music before a game helps a lot of players. Play with the ball as much as you can before kick off and run through playing the game in your head as if you were watching a movie. Warm up properly and just focus on what you can control.

Set target goals for the game. (example: make 10 good passes in a row, or get 5 shots on goal)

It can be anything, it differs from person to person, but if you look closely enough you might find minor differences in your pre-match routine that may throw you off when you are actually playing.

kicking badly on poor flippin ball