How do you go about purging your mind of a bad thought?

All afternoon long I have been trying to purge myself of the thought of my cat Splotch being mowed down by that SUV, and the throes of death that followed. I tried to take a nap and sleep it away; didn’t work. Tried music, that did not work. Tried to Fluther it away, and that failed too. Every time I see her brother CK, wondering around with less pep in his step because she is not pouncing him spurring a game of hide and seek, that moment pops right back in my mind. It keeps playing over and over, like a bad YouTube clip.

Have you had a memory like that? Tragic event at an air show where someone “bit the bullet”, motorcycle race, witness to a terrible car crash, etc? Short of becoming blitzed, hammered, stoned, etc. how did you get the memory of it out of your mind?