I don't think it's actually that bad when you're an adult. I was stung a TON as a kid though, so I have an irrational fear of bees now, so I guess it hurts enough to do that.
Same Flux. I wasn't scared at first though because I just saw a bug wizz past my face, and deciding it needed to die, I smacked it. However, I ended up knocking it right into my eyebrow and that thing stung me pretty quickly. Wasn't until I pulled out the stinger that I had realized it was a bee.