Actually, I have no problem at all with the hostility. In fact, I think it adds to the atmosphere! You have no clue who to trust, which means that those few friendships you earn are really worth something. My first encounter with another player was really cool, we spent the first few minutes just aiming at each other while discussing, until we came to the conclusion that we are both new started characters without any inventory space to loot each others stuff. We ended up cooperating for a couple of hrs, which felt good :)