My problem with quarterbacks

We all know that any football team needs a quarterback. That's pretty much a given. It would be hard for one to argue that point. Sure, we could always just run, but think of all of the problems that brings. One, the deffense always knows what the offense would do. There's nobody to pass, so of course, it's going to be a running play.
So, we need quarterbacks. But really, what do quarterbacks do? Sure they do account for many of our touchdowns and the game may not be as interesting without long TD passes, but it really irks me that all they do is throw.
Am I the only one that thinks that the quarterback should be able to take a hit? There are so many times when instead of making an attempt to run the ball, to maybe gain 2 or 3 yards, I see a QB throw it away. Why? I know I'm still somewhat of a football novice, but this really doesn't make much since to me. I understand that we need our quarterbacks and we don't want them to get hurt, but this is rediculous. It's gotten to the point where it seems like they are afraid to take a hit. Anyone who's a Houston Texans fan, early in the franchise, rememebers how shaken up David Carr was. Why? I mean, sure he was a bit gun shy because he wanted to get the ball away before the sack. I get that. I fully support throwing the ball away, rather than loosing a few yards on the sack. But much of the time, at least whenever I watch, it seems like the quarterback is available to run a fews yards. Maybe I'm wrong, but I just hate seeing the quarterback deep in the pocket, searching for an open man, nicely blocked by his O-line, and then after a while a deffensive player gets loose, so he is forced to throw it away.
Sometimes, you will see a quarterback go for a few yards. Other times, and from my p.o.v. most of the time, the QB will throw it away.
I've never played football. I've never felt the pain of taking a hit, but I really want this explained to me. Why don't QBs go for it more? Or maybe it does happen a lot and I just don't see it. That could very well be the case. I would just really like some input on this, because everytime I watch a game, whether it be high school, college, or professional, I see this pattern.

Haha. Wow, just as I am finishing that last paragraph up, Texans punter Matt Turk, gets hit. The commentators started talking about how Turk is a big guy and can take a hit, and that he might just be acting, trying to draw the penalty. haha! So can Turk take a hit? haha! I just thought that was great timing, since it is so greatly associated with what this post is about!