Stage 1 - Discovery:You've finally found other people who like the same thing as you do. It's fucking great. YOU ARE NOT ALONE.
Stage 2 - Involvement:You read up about theories and headcanons. Join the community. Start getting excited about new episodes because OH MY GOD NEW THEORIES AND GIFS.
Stage 3 - Obsession:You ship things like burning. Fanfic has replaced actual books. You know every actors' name, date of birth and marital status. You follow all the actors' twitter accounts. You have seen every episode several times. You stay up until ungodly hours to watch new episodes. You spend days downloading HD Logoless Screencaps. This is the best stage ever because everything is RAINBOWS and BEAUTIFUL.
Stage 4 - Realisation:There are some people in the fandom who are idiots. They are horrible about your ship. They talk shit about your favourite characters. People write hate and start arguments. This ruins the new episodes for you and you can't enjoy it anymore. The new episodes aren't as entertaining as they used to be. You're realising that the show is going to the shitter. People accuse you of not being a 'true fan' and the fandom is divided.
Stage 5 - Acceptance:You find a nice, quiet corner of the fandom to retire to. Sure, you keep up to date with the latest episodes on occasion. You still reblog gifs and screencaps, but you prefer the 'golden seasons' when you enjoyed the show and the fandom. You slowly start to migrate to other shows, but your first fandom still holds a special place in your fangirl/boy heart.