First day was awesome for me.
Most of the class was friendly, teacher was a douche, we all bonded over the douchyness of our teacher. There was a bullyish group, but we were like "fuck you guys" and then we all became friends. And our form/homeclass/whatever else, became epic.
I made some good friends that day o7
EDIT: Also made friends with people from other years, one guy was 4 years above him, and he was all badass, so we were like "fuck you too man" and he became friends with us, now he is in the Airforce training for SAS. Fuckyeah.
EDIT: Marco is right, the guy I sat next to on day 1 is still pretty much my best mate. Choose wisely young ones.