Few things strengthen your "Nope!" muscles like motherhood. As a recovering people-pleaser, pre-motherhood me was starting to get better at setting boundaries and opting out of interpersonal drama, unprofessional nonsense, and other things that just didn't serve me well, but I still didn't quite have the hang of it. While every woman, mom or not, should master this skill, I've found that becoming a mom helps you stop taking other people's sh*t like little else.
I remember once, when I was pregnant with my son, I had spent an entire day traveling and handling work meetings, and someone asked me if I wanted to add an additional unpaid task to my schedule. I quickly said no, but the person came back, attempting to guilt trip me into changing my answer. I looked them straight in the eye and said, "My original answer stands. I don't have time or energy for that, and it's unfair of you to expect me to donate my time to you." The person looked shocked, clearly not accustomed to actually having people stand up to his pressure tactics.
While in the past I might have possibly tried to fabricate an excuse or some other way of declining while flattering his ego (or worse, agreed at my own expense), my pregnant ass was tired. My baby was using the energy I normally would have spent preserving his ego to make a kidney or something, and it just couldn't be helped. Plus, something in me recognized that if I dignified this request, I'd probably be on the hook for countless others. There's no reason I should have to spend more time and energy fending off those requests, or feel pressured to accept them, when I could just teach this person that what he's doing is actually unacceptable. (Also, consent much? In all areas of life, "No" should not be considered an invitation to convince me, thanks.)
When you're a mom (and this goes for all moms, whether your work inside or outside the home, whether you're a biological mom, an adoptive mom, a step mom, or any other kind of mom) you pretty much always have bigger fish to fry (and, probably, at least one kid who won't eat that fish because it "looks weird and is touching everything else on their plate"). Even if you wanted to mess around with somebody's foolishness, you really can't, for the following reasons: