To add to what yoshi said above, I find it helpful in those type of situations to say to myself, “This is just a test from Hashem. The person who did this is just a shaliach. If I were on camera right now, how would I react?”
In fact, I heard that that is the rationale behind forgiving everyone who has harmed you in the “Ribono Shel Olam” before krias shema al hamitah. Why would we forgive all who have harmed us during the day? It is an expression of emunah. We are acknowledging that it was sent by Hashem, the person who actually insulted us, etc. was only a shaliach.