I went to my junior prom, didn't particularly enjoy it. Asked a girl to the prom senior year, she turned me down (she had strict parents and I think she wasn't allowed to go, period), so I skipped it. Went to church with my parents that night, actually. :-)
And the clique thing at reunions is universal. Many of the same people who were nasty in high school are still nasty 20 years later.
Funny you should say that. A friend of mine who went to her 20th said all her old insecurities resurfaced when she walked in the room, all the same groups re-formed. It was not a pleasant feeling, to say the least.