"You can't start the next chapter of your life if you keep re-reading the last one." Stop thinking about the "what if". Reflect on "what is" and create the "what's next". Be in charge of your life. Start your next chapter. Be the author of your own story.
Sometimes you just have to close your eyes, count to ten, take a deep breath, remind yourself that you wouldn't look good in prison stripes and just smile at that dumbass and walk away. Well, not just sometimes.