When you talk about GC all.the.time. and you play their music every single day and you turn on E to see if any mention is given, and you get on the internet ever single day just to see if they've left a blog, and you love everything about them.
when you know every word to every song, seen every video and can quote them anytime.(people are always like "what the hell are you on about?"..its like an inside joke with a couple of friends)
You know you're obsessed with GC when you live and breath GC and think about them 24/7. When you name pets after them (my 3 guinea pigs: Joel, Benji and Billy LOL) When your whole wardrobe consists of GC t-shirts and hoodies. When you can associate every aspect of your life with something Good Charlotte has done. When you hear someone say "Good Charlotte" or Joel Madden etc. on TV and you stop and look and your heart skips a beat. When you hum Good Charlotte music under your breath all day long.... I could go on and on.