Great article from Psychology Today on invasive thoughts. Here’s a taste:

• Your job review is scheduled in two days and, in passing, your boss says, “Well, we’ll certainly have a lot to talk about.” You try to put what he said out of your mind—what did he mean by that?—but it keeps coming back, and now you’re a nervous wreck.
• You’re sitting in the airport, ready to board, and thoughts of every plane crash you’ve ever read about keep barging into your head. You try to shake them off, reminding yourself that plane travel is safer than driving a car, but it doesn’t work.
• You’re going to the doctor next week to have that mark on your thigh looked at and you think it’s probably nothing, but worst-case scenarios float into your head 24/7 and distracting yourself doesn’t work. Why is that?

The answer is what Daniel Wegner calls “the ironic monitoring process”—your brain actually searches for whatever thought or emotion the individual is trying to suppress. Yes, your brain is actually nagging you…