My daughter laughed and smirked when I was being serious...once.
I’m not the most patient of men, and at one time had a pretty good reputation as something of a bar fighter. I would introduce his smirk to my left hand. Seriously, I couldn’t put up with someone laughing while having a serious discussion.
Someone laughed and smirked at ME, once, at a board meeting. I stopped the meeting, confronted him directly but calmly, and asked him to apologize, which he did - in a squirmy, worm-ish sort of way. He resigned several months later. People are thrilled, and I am still Prez. (He was lucky I did not push his teeth down his throat.)