I've got three kinds of friends
1. Friends I talk to during work and in school. Maybe go out sometime to grab a cup of coffee and have a chat. (Easy to belong to this group - If I can talk to him/her and have a conversation not just Hi or Good bye they belong in this group)
2. Friends that I feel comfortable around and trust to at least 70% and can talk to about most in my life, movie night pals, shopping pals (kinda hate to shop but with the right company it's bearable) and so on
3. These friends I trust to 100% and feel totally relaxed around and know I can be myself without them judging me and know they will stop me if they think I do something wrong.
The 3rd are hard to find but I'm lucky enough to have 2 of these and a 3rd well on her way ^-^