Brain: So you know that sad event that happened last night?
Me: Yah? It was unfortunate, but I really don't want to focus on it right now.
Brain: But we should.
Me: We shouldn't.
Brain: We should. Because what if? What if we could have done something differently to make that outcome better? 
Me: Since it's already happened, we can't do anything to change it.
Brain: But we should still consider everything we could have done.
Me: No. 
Brain: Yes!
Me: *pulls out distraction* How about we think of this instead?
Brain: Oooo!!  *distracted*