sleep at 11?

impossible! that was by statement this morning when i suggest him to sleep earlier.. he is a night person, happiest to stayed up very late,, occupied himself with many things to do and he claimed its his productive time. but i never came to understand it coz im worry for his health.. but now i lose the patience to talk about it nicely.. rather than hoping he will change his sleeping habit soon,, i wish he will get his iphone soon.. ^^