That and, well, teenage hormones/narcissism/intensity. Their behaviour doesn't surprise me at all -- I remember most teenage relationships (of my friends', since my teenage crushs were all unrequited...) being tiresome in just this way: enthralling to the two individuals concerned, a right pain in the neck for anyone else who just wanted to get on with their lives normally and not constantly find themselves accidentally barging in on a Deep and Meaningful Moment of some kind....