I do this too but not sure it is related to ADHD. I am an introvert and I avoid confrontation when possible when another is being disrespectful. After, I’ll brood for a long time. It’ll linger in my thoughts, especially when my mind starts to wander (so, maybe ADHD related). I’ll carry that grudge for quite some time. If the behavior from that other (and here I am thinking of a current brooding issue w/a brother-in-law… whom, sadly, I will be seeing in two weeks) continues there will come a threshold where non-confrontation gets trumped by the ADHD amplified emotion response. Then, I lash out furiously (I even, in a way, fantasize about it in my brooding) and deliver a particularly nasty dressing down and declaration of contempt. I’m never proud of those moments. I have difficulty with proportional responses. Other times, I’ll just hold a grudge and be snidely passive aggressive (I tend to do this with closer family members.. I can control that lashing out here. Instead of a short nasty burst it is a slow steady trickle).