I don't have a problem with Sam wanting things for himself. I don't even think it's a weakness; it's a good thing about Sam, and it's made me sad to see that aspect of Sam so diminished. Show has made the point again and again that self-sacrifice is often destructive and certainly not a virtue. But there's a difference between accepting a loss and deciding to react by finding some happiness, as Sam wanted Dean to do and Dean tried to do after 5.22 and even somewhat succeeded in, and Sam, from the spoilers, not even trying to find out what happened to Dean. That's not a self-centered streak, that's kind of pathological.