I find it's a cruel trick people, usually inadvertently, play on me at work: "when you've got a sec can you look at x?"

There's a portion of my brain that's immediately hijacked and starts thinking about the problem whether I'm actively working on it or not.

Happens to me for work problems outside of work, too. I'll just be chilling in the shower or something and suddenly I'm thinking about a work problem.

Maybe one day I'll retire from programming and do something less theoretical e.g. driving a semi.