When does too much positivity stop being an asset and become a handicap instead?

My good friend, who I also live with, is always trying to look on the bright side of things. Everything is cupcakes and butterflies to her. She seems to do fine socially and have no real problems with anyone, but never actually gets close to anyone. While I think she is quite the gem, I think a lot of the people she chooses to hang out with are superficial and fake.

When it comes to our living situation, she would prefer to live with people who are superficial. Our last roommate worked our horribly, so this time I was really harsh about who we chose. She wanted this girl to move in that no one gets along with! (She just wants to make friends that asset her interests: like the music biz).

Anyway, the point is this: would you rather be incredibly positive, always trying to look at the bright side but have no real friendships, or would you prefer to be more negative but at least have “real” friends? Why, if my friend is so sweet, does she enjoy hanging our with these people who are fake?