It is something you don't think of, unless you have them.... so... been there, done that.
This is just like when people stare because I'm fat. As though I have nooooo idea that I'm fat, and they're sooooo subtle as they stare. If I look at you looking you should know your casual gaping has crossed the borders of politeness into apparent staring. Your mother would be ashamed your behavior, or at least mine would have been.