Be kind to your co workers, but you're there to work... Not make friendships. In past jobs, I was always the person people chose to talk to, but I hardly spoke to anyone on a personal level. Call me keeper of secrets.
As for the work spouse phenomenon, uh uh, not a good idea. When I worked in the ER, I observed many "work bf/gf" relationships turn into "Lithe, I need to tell you something! I cheated on my spouse and now I'm marrying the person with whom I had the affair! Aren't you happy?"
Yeah, may you two live the most blissful days wedded in happy absurdly blessed matrimony.
*insert eye roll here*