Bosses hate it when their employees have more than one job because secretly (or sometimes not so secretly) they want to own all of your time. Redditor u/AZNM1912 already had a full-time job and didn’t really need their extra part-time gig, which gave them the upper hand. OP’s part-time boss knew this, and yet still threatened to fire OP unless they started working for them full-time. OP happily left, of course, and their already understaffed boss totally shot himself in the foot. Pro tip: if you’re desperately understaffed, firing one of your only remaining employees is probably not the move.