selfish

The word most commonly used in a negative context of describing a person or an act. Its not a word that describes a person but its a word that describes a person from the perspective of the speaker. A person can only be described correctly with one sentence. 

HE/SHE IS WHAT HE/SHE IS

Nothing more, nothing less. Everything else is just perspective. Just judgement passed by someone else based on their capabilities, based on their knowledge, based on their wiseness and even based on their selfishness. 

Actually, I don't see the difference between selfishness and selflessness. Both have opposite meaning in dictionary. An act which is done for self is termed selfishness and an act done for others is termed as selflessness. The act is still done by the same person. He does this act, because he wishes to do it. Fulfilling a wish of your own is also an act of being selfish. The practical or visual result might vary based on what the act is, but still the wish to do it, makes anyone selfish.

Does this mean, its good to be selfish ? Any act that gives you happiness is a good act. Be it selfish or selfless. If the result of the act makes others happy along with yourself, then even better. 

Does it mean, being greedy is also okay ? Its important to understand what happiness is. When happiness is measured or viewed materialistically, its greed. When happiness is viewed in a sensual or spiritual way, then greed would not govern the act.