I went to my 10 year reunion at the insistance of a friend (who "won" the reunion--he has an awesome job and does stand-up and basically felt like he put everyone who ever picked on him in their place).
I was nervous because I feel like a loser (my biggest accomplishments thus far are an associate's degree and a kid).
I also didn't want to see 2 people--my former bff whom I stopped talking to and the guy I was dating (and REALLY liked) when my now-ex-husband decided I should be his girlfriend. When I found out the girl wouldn't be there, my friend told me I had no excuses not to go. I saw the guy I dated, and it wasn't as awkward as I expected, though, I was secretly hoping we'd go out again...oh well...
Plus, it helped that a lot of people got really fat...I know that sounds bad, but some of the more athletic people from high school really let themselves go. I had a kid, and don't weigh much more than I did then, so I guess that's something.