My dad, may he rest in peace, was one of the wisest men I ever met. He'd say, "Don't look for malicious intent where stupidity suffices." Translating, people are far more likely to be stupid or clueless than they are to be evil or actively seeking to harm (or even upset) you. Just move on, and if you need something to comfort you, remember that you had to deal with that person just once. He has to live with himself for the rest of his life...