Well, nothing about the universe actually makes sense. We just think it does because that's how we grew up. Why does light have a set speed? Why to particles attract each other (gravity)? Why do things have mass?
EDIT: These discussions are always interesting to me because no one can win
In fact, light moves faster or slower in other mediums than vacuum (sorry for the mistake with water, lol, but there is a material in which where photons can move... Wait, no, I think it's wr... Aaaargh! I'm confuzzled, but I think there was a material where photons could move faster than in vacuum, strange... I know there is something where light moves slower and molecules can move faster than the light, but perhaps that's what I'm confusing it with)...
Anyways, the discussions are win-able. I often discuss on the EA forum and it isn't that hard to win, most of those in there don't really know so much about space, biology and stuff, so...
Okay, there are some other clever people in there, but usually they're on my side anyways.
One of them actually posted a great page with evidence for evolution. I'll post it if you want to see it.
Also if you want to see any of the other discussions, I can post them too.