friends or not friends?

have been reading emails, blogs and other stuff lately. suddenly, I came across something that really catches my eye. roommates. are they friends or plainly just roommates? it made me thinking. when you are choosing a roommate, shouldn't that person be someone you trust, someone you like and someone whom you feel easy to be with? at least that person should be someone you call a friend. am I right?

is it possible to be in a room with someone you hardly like and hardly is your friend and spent your whole college life with her? then why there are cases where you don't share your life with your roommate but with someone else? if that someone else is whom you trust, why aren't she your roommate?

for me, my roommate is someone I trust, whom when I have problem I share with and I share everything I could with her. I share my joy, my sadness, I tell her stories about my achievements, about my worries. I felt easy with her presence and I worry when she suddenly disappear. am I doing the right thing? or I'm being overly controlling? should roommates also be the best of friends or they could just be roommates? where you came into the room, do whatever you like, don't talk to each other, and leave?