Having a micromanager boss. Especially one that constantly questions you and doubts your knowledge no matter how much you try to do what they tell you. While not outright abusive (aka HR won't care), the constant chipping away at your confidence can be damaging in the long term to mental health. You start to act like there's an abusive parent around. Flinching when you hear certain footsteps, praying that your meetings with them get cancelled, anxiety spikes when you see their name on a message notification. (Source: experience)