I tried setting boundaries with a CTO who was pressuring me everyday to work on an "optional" side project. I hated working with him because he wanted control over every little detail. On large projects it was easy to just do tickets. But something small, I had to listen to his bs thoughts and criticisms constantly. More so than working.
After I told him I didn't want to do it 100 times I finally gave in and said it was because I didn't want to work with him specifically. HR contacted me the next day and said some of my comments made someone uncomfortable. They couldn't say what, or who.
This happened 6 times over the next couple of weeks. At 3 I stopped talking to anyone, period. Just to test it out. Still I was saying nasty stuff to someone.
Needless to say I was fired without reason and never given a chance to talk about what was happening, because nothing was happening.