I was talking to my bff today about what we can control. When I asked her what she thought about what we can control, and if we can "retrain our brain", she quickly said (and she's old like me ) the only thing we are able to control is our reaction to stimuli...which of course I agreed with. lol She even said (as has been pointed out) that changing one's routine and/or having a planned activity such as a puzzle nearby or a book or plan to do an exercise when you have thoughts or day dreams of something you don't like or want pop in your head. She went to a therapist years ago....she knows a few tricks.