>Does happiness end with your teen years?
Nope, just puberty and high school.
I always pitied miserable people, when I was in my 20s. Whenever I saw a movie about drug addicts, or villains whose sadness, nihilism or anger created the conflict of the story, I thought about how not to be like that, because I found it pathetic: these dumb bastards all waste their lives because they can't conceive of just moving on from their tragic backstories.
Maybe the common denominator to these characters is that they drag the past with them like a ball and chain.
But then, Batman had a tragic backstory, and you have to wonder why he became a hero instead of a villain.
I think the answer to that comes down largely to aesthetic sense, the ability to care about more than his own needs, and optimism about people and the future. It's these qualities, more so than a willingness to wear your undies over your pants and jump off buildings, which defines "heroism."
Modern life requires a little heroism.