Reminds me of this Ask Metafilter thread:

As far as I am aware, I am a mentally healthy, well-adjusted, and sane person with no disorders. But I have a strange, fairly innocuous quirk which seems beyond my control and I'm curious about it...

When I think of / remember something embarrassing from my life, I compulsively make some kind of noise. It seems to happen unconsciously, before my censor can catch it and stop myself (it even happens when I am in a quiet or inappropriate place).

[a bunch of other folks chime in confirming that they have similar experiences, and one user writes]

I am convinced it's the people who don't do this who go on to be rich, leaders, etc.