What is existentialism?

It's the philosophy that we live in an indifferent and harsh universe where the bottom line is that life isn't fair. Have you ever asked the question, "Why me?" when something terrible has happened to you? Existentialists would know better to ask that because they believe that nature has no rhyme or reason as to why it dishes out pain and suffering. They stress the isolation we experience as individuals alone in a cruel world that will more often beat us down than lift us up.