Don't ever underestimate anyone. Some people are silent helpers. Those people you never take notice of or you notice then but snob them; at a point in life  become  the reason something good happens to you. Due to a tiny help they offered which you didn't expect to change your life at that particular moment or forever.

My dears, the dullest guy in your class might be the one to deliver your wife from a  troubling labor.

I know its not easy to treat people equally, but at least try not to snob them, greet them , appreciate them and be HAPPY.