All of my fights were minor arguments that were solved in one day and generally didn't truely involve me, just a friend and other friends of mine.
Once, though, I got really mad at my friend two years ago because she was always mean to me and everyone (she got better last year, though) and I kind of yelled at her/gave her the cold shoulder and didn't really talk to her for the rest of the day. After that though, everything went back to normal the next day.
Another time last year my friends got in a huge all day fight. A few of my friends wanted to become 'popular' and sit in another area of our school to eat lunch. We said okay, and they left. They came back about ten minutes later and were screaming and crying at us because they thought we were being mean. They apparently thought it was rude that we didn't decide to go over and sit with them. So, by the end of that lunch everything was okay.