It's perfectly fine if you tell me what I'm doing is wrong and it's totally okay for you to correct me if I'm incorrect, but I think you should stop insisting that you're right because well, it's been verified that I was actually correct.

I've all along been very appreciative of the help you had given me so far, but I'm in a shock that you're actually such a male chauvinist pig who doubts and dismisses whatever I suggested. You may have worked here longer than I did, you may be older than me, you may be more experienced than me, but you should not effing belittle me.

Three more days of work and it's good riddance. Can't wait.