How do you get rid of a bad thought that lingers and haunts you for weeks on end?

I said something, in jest, to one of my students. She took it the wrong way, and decided to be offended by it. I didn’t even mean anything by it – and it had nothing to do with her, nonetheless, she was hurt by it.

Let’s forget for a moment what it was that I’d said, or why she misinterpreted it, as I am okay with that – what I’d like to know is how do I get it out of my head?

You know the song: And I can’t get it outta my head… well, that’s me.