I think a somewhat reliable proxy of how good life looks like to you can be found in the following thought experiment.
If you could manipulate time such that your parents never met, and as such you were never born, would you do it?
Now, before anybody gets worried, don't. I'm not considering harming myself, nor have I done so in the past (unless you consider my love of unhealthy food as "harming myself"). The reason I brought it up was because the first time I asked myself that question was something like 6-8 years ago, during that shitty phase of life known as "high school." At the time, my answer was a resounding "yes."
I don't mean to diminish the seriousness of clinical depression. I know it's a valid entry in the DSM-IV, and that real people have to struggle with it on a daily business and that it has destroyed probably hundreds of thousands of lives. However, I think pretty much everyone, even the healthiest of us, suffers from melancholia at some point in their lives. Anyways, I don't want to get into too many details, and I know some people had good high school experiences, but to me high school fucking sucked. Looking back I can remember how hopeless everything felt like. Every day I would look forward, to see what my future held, and say, "that's it?"
The reason I brought this up was because this night while I was brushing my teeth (I always get introspective when I have objects inserted into my mouth) I asked myself the same question, and I wasn't so sure if, given the above choice, I would take it. I may be just in a good mood tonight (tiramisu will do that), and tomorrow I'll feel crummy because I was sitting at my computer up until 2 in the morning, but right now I think that's a good sign.
I think there are two main reasons why I generally prefer life in college and after (besides the fact that most people are much more pleasant to hang around the more they mature). First, there is this general feeling that my life is more under my own control. It feels (however illusory) that I'm sitting in the drivers seat, and not in the passenger seat, and you know what? True or not, it's awfully comforting. The second is that I'm doing much better at looking at things which come my way and seeing opportunities at best, or obstacles to overcome, rather than things to get discouraged with. This may either be positive thinking or self-deception at work, but nevertheless it's also really comforting.
I'll leave you all on that thought. Good night!