1. Mark criticized Pam’s clothes and in return she criticized his haircut. It was tit for tat 92
2. I didn’t wash the dishes for you yesterday, and today you didn’t take out the trash for me. I guess it’s tit for tat.

Synonym: give (someone) a taste of his own medicine; fix (someone’s) wagon. The expression may describe insults (opt.1) or some harmless error (opt.2).