Nosebleeds!

Have you ever noticed that when a really cute girl walks by a guy, the guy's nose starts to bleed? Me either. O.o Yet, when a cute anime girl walks in front of an anime guy, the guy's nose starts to bleed. Why is that?!
Well luckily I have the answer! Rather than show profanity in the animes, when a guy gets aroused their nose starts to bleed because of the blood that flows to their head.