We're supposing that you might have read about the recent find from the Social Indicators Research scholarly journal, namely that people who are happy evidently don't watch as much TV as people who are unhappy. If you haven't, please read this report in The New York Times. Taking into account all sorts of the other things which people can do -- hang around with other people, go to church (isn't that the same thing?) -- evidently the elusive Television Factor is an indicator of relative happiness.
I'd posit that it's a little more complicated than that -- I'd certainly agree that what you watch might contribute to one's overall mood. Skip the rancorous phony reality shows, the overblown local news with their "if it bleeds, it leads" mentality, the stupid daytime talk shows and you'll probably feel a lot better, real fast. Instead, watch some terrific colorful melodrama like TrueBlood, or some sublime episodes of The Sopranos, or some smart and zesty humor like 30 Rock, or an inspirational historical drama like John Adams, or the cool delights of Mad Men, or pop in an old episode of your favorite sitcom like I Love Lucy, or remember how you felt when talented and charming David Cook won the last American Idol.
Still unhappy? I didn't think so.
I rest my case.