Do you suffer from anything that you simply can't control? Sometimes it just hits you at the most inconvenient time. For example, it could be "insert foot disease", something my wife has claimed I have for many years now, which is where you say something completely inappropriate at the most inappropriate moment. I must admit, I do that quite often.
Perhaps your one of those who uses weird voices when in an awkward situation? Or maybe you sing loudly in the hallways at work? I should probably stop, I'm only describing myself.
Nonetheless, just know you're not alone and at least it doesn't get you in as much trouble as singing gets James Corden and Harry Styles in!