Selfish is a crude word.
We all are designed to be selfish. Selfishness is our primal survival mechanism. If there are only two pieces of bread left in the world, I don’t think you will try philanthropy there.
Then what is selfishness ?
If I take advantage of others out of fun,use dishonesty when honesty was an option, deceive people to use their emotions with survival need, I am selfish.
If I think about me but also about others in the process, I am self reliant and not selfish. Being selfish is only thinking about one self if you have the scope to think about others too. You can be 60/40 in being selfish. That is done. But not 90/10.
I can assure you that 90% of people out there are still nice and good and that is why world is running smoothly.