The oxford dictionary defines Selfish as :
adjective (of a person, action, or motive) lacking consideration for other people; concerned chiefly with one’s own personal profit or pleasure
For a long time, I thought of selfish as meaning doing something for your own profit or pleasure. Even if you considered other people, and chose the option that least harmed others, it's still selfish because ultimately you're doing it for you. When we help others, when we offer guidance, when we do a good deed we FEEL GOOD. Do we do those things because we know it will make us feel good, or because we know it will make someone else feel good? I think, for most people it's both. So it is both selfish and unselfish. I know that I enjoy seeing others happy. But when I am the cause of their happiness (either through giving them something, or giving them my company) it's that little bit sweeter. Because I myself have caused that. Because I am part of that. Because I am connected. I think all we really want is connection, all of us. We want it for us.
In the end I don't think that is 'selfish'. I've come to realize, that selfishness means doing something that raises your own happiness while lowering another's.Even then, that's not always wrong. For example, say a friend wants to see you, but already had plans to stay in with a nice movie which you were in the mood for. Staying in instead of seeing them benefits you, but probably disappoints them a little. But that';s life, a good friend will understand. Sometimes you need to do things for you. When this becomes repetitive, OR if you actually hurt people for your pleasure, I think that's when it can get destructive. But in the end, we are all selfish to a degree, it's human nature. At the same time we want to connect and share and give. It's a balance.