1.Inf. not to miss observing any part of what is going on. (Usually with do as in the examples.) Ted doesn't miss much. He is very alert.The puppy doesn't miss a thing. He sees every move you make.
2.Inf. not to miss experiencing something that really was not worth experiencing anyway. (Usually with do as in the examples.) I missed the big sales meeting last week, but I understand I didn't miss much.Bill: I didn't see that new movie that is showing at the theater. Tom: You didn't miss much; it was pretty bad.