What Are Some Examples of Existentialism?

One example of existentialism would be the idea that when something does not work out or a person does not achieve what they set out to achieve, then this is not because God did not want it to be that way or because of destiny, but rather because the person chose to do something different. In existentialism, it is believed that there is no God and that "man makes himself" through what he chooses to be.