Hating Wednesdays
Karl hated Wednesdays. Since forever.
He had to deal with that certain pest every week. He so hated this day, Tuesday nights were full of anxiety and Thursday nights were.. not particularly that much better.
Then one day, the pest stopped coming.
Karl suddenly found Wednesdays quite relaxing and even.. a little boring.
Thinking about the week, Karl had no choice but to make a subconscious decision to forever more hate Tuesdays.