I have always always always been a Medium. About 6 months ago I stopped at the outlets store during a trip because I had forgotten to bring a few clothing items.  I went into an American Eagle (which I thought was supposed to be a store for teenagers, and I am 30) and the Medium was HUGE. I ended up getting an XS A-line dress and size 4 "shorties" and was so confused leaving the store.  It's only now after FPH that I understand why....