Should we take 100% responsibility all the time for things that happen to us?

I was listening to a motivational speech that was given by a success coach from a university and in a nutshell he was saying that we hinder ourselves from success because we generally like to always point a finger at someone or something being the cause of our failure and not taking 100% responsibility for our failures. He says taking responsibility for how we think, determines our success. I was pondering on that and what he says may be true at one point of view. What about the horrible things that we have no control over that causes us to fail? I think that there are things in life that we just cannot control and that taking 100% responsibility might be unfair in some circumstances. What do you all think?