You believed that's the way things worked when you were 19, because it did.  And now when that you're 30+, it's different. You're not smarter, things have changed.<p>For men, the late teens to mid-twenties is the period where most mate competition takes place.  This is where testosterone rates soar, as do accidental deaths as a result of risk-taking behavior <a href="http://www.epjournal.net/filestore/ep026685.pdf" rel="nofollow">http://www.epjournal.net/filestore/ep026685.pdf</a><p>No one you knows fits that description because like you said, everyone you know is in a relationship.  What I described happens when people are trying to compete over mates.  When everyone has a mate, i.e. past their mid-twenties for most part, they become much nicer.<p>Well, except for the occasional 30+ yo that likes to make cheap shots about folks over the internet via an implied link between maturity and intelligence.