I graduated last June and what I do miss:
The group of friends I had...I was new to the town I went to HS in in 7th grade and I befriended a few people who I still keep some contact with today.
The easiness of classes...I graduated with a 3.4(89 weighted) with little effort...if I had not taken Calculus senior year it'd probably have been more like a 3.5, but oh well.
Some of the teachers and the smaller classes...Most classes were 20 people and you had the ability to...shine, in a sense. I'm current a business major, but I found history quite easy in the classes I took in HS, or maybe my classmates had a lack of knowledge/interest that made what I knew seem like..a lot.
What I don't miss:
-The annoying people that I'd have to put up with...no way around it.
-The schedule...waking up at 6 or so in the morning sucked, no question...the college schedule sure is one worth paying for
-The lack of variety in classes...You needed 3 years of science, and there weren't any real options...I sucked at Chem and Physics, and was meh in Bio. In college we have more options.
What do I regret?
-Not taking more honors classes/any AP classes my senior year...I took 2 honors classes senior year and I felt more challenged and that I was in with a group of kids that were at more of a similar level that I was at. And when I got to college, most kids already had anywhere between 6 and 30+(!) credits...and the fact that NY has regents and NJ doesn't...does not help me.
-Not going after certain girls...but oh well, you can't really dwell on the past.
-Working more...I worked weekends at a grocery store, but I know I could have done hours.
-Not getting my license until I left for college...I felt senior year would have been more enjoyable if I had a car and could have come later, left at will, and gone out to lunch.
And I kind of regret going to a college where nobody from my graduating class went, but I guess it's starting on a new slate, although I don't think I'd have regretted staying local.