Opening the book…
Most slights are not aimed at you. People are tired, distracted, or fighting something you cannot see. Assuming the worst is expensive: it sours the relationship, invites a defensive reply, and is usually just wrong. The generous story costs nothing and turns out to be right far more often than not.
Before you respond to something that stung, write down the kindest plausible reason it happened. Then send the reply you would want to receive on your own worst day. If the generous story turns out to be wrong, you can always address it later — calmly, and with the facts in hand.
Generosity is not the same as ignoring a pattern. When the same thing happens again and again, believe the pattern over the story. Good faith and firm boundaries are not opposites — you need both.