Happened a while ago but just found this subreddit.
My buddy owned a taproom and really needed help finding cooks. I had accepted a job that would pay me a very good wage. I wasn't doing anything besides playing video games and drink so I told him I'd help!
I had season tickets to college football (the university I just graduated from). I told him and my direct manager that I'd agree to work if and only if I could make every home game. Everyone agreed and it worked beautifully for 3 weeks. The manager tried scheduling me on a game day. I immediately told her I couldn't and she said “If you go to this game you might not have your job” I answered with a simple, “That's fine” all of a sudden she changed her tone and immediately worked to find someone to cover the shift. She did and I continued to work for 3 more weeks before leaving for my original job. She also was fired shortly before I left cause she was a terrible boss.
It is amazing the power you have over a job when you don't need the job!