I had one auspicious occasion when I did that 3 times in a row. Changed stitch, forgot to change setting, broke needle. Carefully changed needle. Forgot hadn't changed setting. Broke second needle. Lather, rinse, repeat. Didn't even move from my chair.
Broke all 3 needles (metal foot so no harm there). I'd say I don't know what was going through my head, but I'm afraid the answer would be 'nothing'!
I did figure it out eventually...