Say what you saw, not what you assumed. “You were late” beats “you don’t care.”

Facts can be answered and motives cannot. Telling somebody they do not care makes a claim about their insides, which they will deny accurately, and now you are arguing about their character instead of the thing that happened. The observable version keeps the conversation inside territory where you both have the same information. It also leaves room for a reason you did not know about.

Before the next complaint, strip it down to what somebody could have filmed. Say that, then ask what happened. You will be surprised how often the motive you assumed turns out to be wrong.