My ex-girlfriend's dad once told me "Mike, you're kind of an introvert aren't you?" to which I just smiled and nodded in agreement... Then one time when I was 6 years old in kindergarten, all jacked up on mountain dew and running around the class room, truly the life of the party, I remember the teacher describing me to my mom as being a total "extrovert"..
Either I'm some rare breed that can go back and forth to whatever suits me, or the whole method of classification is a bunch of bullshit