Without exception, we have all done something embarrassing in public, or at the very least, something that would cause embarrassment if we were discovered doing in public. For example, attempting to ninja fart in public, or perhaps something more dirty. Another example would be stomach growling loudly in a quiet area.
You may think no one notices these little quirks, but people are more perceptive than you think. They may have noticed but just do not call you out on it blatantly, after all, it would be pretty rude for something minor.