A couple times. Once when I was in my early 20s. The boss told me to do something that I thought was stupid so I refused. He fired me on the spot. Later in my life I was at a company that was slowly going under. I'd given up and was just marking time. I got sacked for lack of performance but because they didn't have it documented I got a severance package. Didn't matter because they shut down before i ever got paid.