This is the post that's going to keep me off the Supreme Court (after Harriet Miers, anything is possible).
For whatever reason, G-d (or nature for the G-dless out there) decided that the optimal situation is for men and women to form a life lasting relationship, wherein they can build a family. But anyone who has ever met a member of the opposite sex knows that men and women are very different and have different expectations in a relationship. These differences create lots of tension and often cause a relationship to break down.
Dating is treacherous terrain. Even the most amicable breakups leave one or both of parties bewildered. The breakup, or the actions leading to the breakup, is usually confusing.
Men and women (or women and men for the feminists) are very different. A serious male/female relationship is tilted toward the woman. Why? Because these relationships are predicated on openness, on a willingness to talk about issues, problems, or whatever else is on the parties' mind, and about forging an emotional bond between the two. Girls have these types of relationships growing up. They talk about their feelings with their friends. They talk about their problems and difficulties. They sit up to 4 in the morning talking about something that's bothering them. Girls are therefore better suited to create an emotional relationship.
Guys do not do that. Guys rarely, if ever, talk to their friends about feelings. Guys are emotionally stunted because they do not acknowledge their emotions, unless that emotion is anger or frustration. So they have no idea how to be open, and they have no idea how to deal with relationship problems.
When two girls have a fight, they either work it out or they stay upset at each other. Guys don't. It usually boils over and everything goes back to normal (obviously this is not always the case). Guys focus less on their emotions, and they surely are not willing to share them with their friends.
So when a relationship has problems (which is inevitable) the girl is all ready to work them out. The guy, on the other hand, is clueless and has no idea what to do. So often times, he does something stupid, which only exacerbates things even more. And the girl has no idea why the guy is acting that way, so when they break up, she's at a complete loss.
But guys are not the only weird ones. Girls, because of their emotional openness, act less rationally. Yes, girls are completely capable of being rational and I've met quite a few in my tenure at law school. But girls allow their emotions to take over and stunt their rational thought. Guys generally don't (again, unless that emotion is anger).
Sometimes a girl will do something and the guy will just be left thinking, "what the hell is she doing?" The guy can't respond because he can't understand. The girl, who is no longer thinking rationally, expects the guy to comprehend. But he can't because there's no rational thought involved. Guys aren't mind readers. So, as a result, a serious miscommunication results, leaving both parties completely bewildered. And coupled with the guy's inability to talk about the problem, the rift only gets wider and the relationship breaks down, leaving two confused parties in its wake.
These problems are not really fixable. But guys and girls can try to deal with them. Guys have to try to become more open. It's not easy, but girls really do expect it and it's actually pretty normal. Girls have to understand that guys aren't mind readers. We can't figure out what you're thinking, especially when you aren't really thinking.