Some people don't really and truly invest themselves emotionally in a relationship. They are into speed dating.
Absolutely no clue, but immaturity has to play a part. No one can convince me that it can be 'real' every 5 minutes.
yes, i am a disbeliever in this one myself... i have never recovered in weeks or even just a few short months from something long term. if you're genuine you do part with some of your energy and it takes precious time alone and recapitulation of the experience to regain that energy. i am with 151rby in that i think some folks are being fake about it, and i guess synthesizing emotion in this way is what modern day narcissism is.