Got sacked from a succession of crappy Saturday jobs as a teenager - because I was basically incompetent and lazy.
I worked in a garage for a short while, sweeping/mopping/cleaning up after the mechanics. They replaced me while I was on holiday. I only found out when I went in to do my first shift after getting back, and found someone else doing my job.
I then went to work in a petrol station. I was sacked after the second time I put petrol in a diesel car.