There are so many things and events that will occur during your four years at high school, so I believe that in no way can you look back and say you will only miss basketball, drama or band. It will be more suitable to miss the memories. Go through a normal full-length day and think about all of the memories you have taken in during those eight hours. There are things like the party you went to the weekend before, the choir concert you put on for your school, your homecoming dance, the last performance of the play you are in or your senior year. All of these things stick with you, so that when you come back 20 years from now, you have things to talk about and laugh about with your friends.
High school is so complex with extracurricular activities and tests and dances and performances.
Instead, they exist to give you the one thing that every person should have the right to experience - memories. That is what I will miss the most about high school, and I believe that when you take a second to look at the memories from your high school career, you will agree. There are a lot of things you may selfishly leave out by narrowing the things you will miss down to a single subject. Think a little broader than that. As for myself, I can miss anything that was appealing.