Probably more a new paradigm is needed than a balance between selflessness and selfishness.I do plenty of nice things, but in my view, it's at least somewhat selfish because I want people to think well of me and do nice things for me back. And when people do nice things for me, I try to return the favor as they prove themselves worth having as a companion in life--though I'm careful about the psychic vampires and other scum. (EG, one guy gave me a ride when I was 15 and bought me a pepsi and then tried to rape me because I "owed" him.) I don't begrudge other people their selfishness, either. Heck, by thinking of others, I'm thinking of how to indulge their selfishness...generally for my own selfish purposes. Ideally, everyone benefits.
Granted, I sometimes do things that don't benefit me at all. EG, I recently came across a child's book shelved in the adult section and moved it to where it went. I've also cleaned up a mess I came across as all the other librarians were too busy, and I've helped some unpleasant people (though there are limits to my patience on that). In a store parking lot I ran to catch a buggy that was rolling out of control and about to hit a SUV. There was nothing selfish about this, though one could argue there's something compulsive about it (maybe I'm a little OC, similar to some neat freaks).
Non-selfishness can be evil, too. EG, someone who works in a prison told me that one of the people in the prison was found innocent after the cops who busted him had been caught planting evidence. True, that was selfish of the cops because by amassing easy busts, they increased their pay and rank (at least until a whistleblower turned them in with evidence). The innocent guy tearfully thanked his god. But--for no selfish reason at all--the prison guards transferred the innocent guy into a cell with a guy known to have a yen for killing Christians, which happened (so the innocent guy was released the next day as scheduled--only to the morgue). To top it off, the satanic killer was then transferred to another wing to protect him from retaliation as the murdered Christian was pretty popular among some of the inmates who would likely avenge him. Why? Not seflishness as they took a risk onto themselves (as it happened, one person got a small paycut over it, and he wasn't really responsible for it--the guilty ones covered themselves too well) for no gain whatsoever. It was not done out of selfishness, but out of sadism that was not in their best interest to indulge (unless they just took too much pleasure out of things like that--which means they're wired really different from me who would be sickened to do something like that and hates to watch others in misery).
And the ultimate selfless person is like the suicide bomber.
When I think of the truly selfless, I think of the Borg from Star Trek. It gives me the willies.
I see myself as selfish, but I do have empathy and compassion for others, and I feel my connection to them. To me, my sadness is lessened when I share it, so I nurture friends to share it with and share their sadness as well because I don't like to see them sad, and because I'll eventually need them to do the same for me.
At the same time, my happiness is increased by sharing it. Like watching a funny movie, for example, is much more funny to me if someone else also laughs at it, so I share it and we all benefit seflishly from each other's happiness.
Nothing wrong with selfishness, IMO. Now OBSESSION--be it selfishness, or selflessness, or love or hate (or both, as it can be), and all that is bad. That is, COMPULSION is bad. Or maybe a better way to put it is IRRATIONAL selfishness/selflessness as opposed to rational selfishness/selflessness.