Give the person the benefit of the doubt. We teach people who face a gap to ask themselves, "Why would a reasonable, rational, decent person act this way?" By asking that question, you avoid jumping to conclusions or making assumptions that can move you to make wrong diagnoses. It also prevents you from beginning your conversation in a way that says in essence, "I have held court in my head and found you guilty. Can we talk?" Such a beginning is not helpful and makes you part of the problem.