intimacy

lately Ive been wondering about why humans crave intimacy. like everyone wants someone to be there for them, mostly in different ways. but in short they want to let someone else in, let them know something about themselves so they can be close. but why? why is it that humans are designed to want someone else?
im sitting in the loungeroom waiting to go to work on a sunday morning at 7am (urgh) and i cant help but wonder why it is that humans do the things they do. why do we sleep? why do we eat? why is it that when a person doesnt get much sleep or has a "bad night sleep" that they feel this way? lol.
i have had one coffee in the past week and no V, which could explain why ive been so tired. but im still not sleeping, which makes me wonder whether i should just go back on the caffaine lol. some nights i get the best night sleep, but the next i have the worst i cant seem to have a middle ground.
anyway i better get to work. sigh...