Why do people ask UPDATE

Why do people ask when you are due? I’m not, I just have a little gut.. I work where I stand in front of people and this guy today asked me if I was expecting, then said I only ask because of your glow.. it hurt my feelings a bit but sadly got my hopes up as well.

UPDATE:

Second day in a row someone ask me about being pregnant. This time it was a lady who asked “do you have a name picked out?”