The only thing that can trouble us is our opinions.

It is not the things themselves that disturb men, but their judgements about these things. For example, death is nothing dreadful, or else Socrates too would have thought so, but the judgement that death is dreadful, this is the dreadful thing. When, therefore, we are hindered, or disturbed, or grieved, let us never blame anyone but ourselves, that means, our own judgements. It is the part of an uneducated person to blame others where he himself fares ill; to blame himself is the part of one whose education has begun; to blame neither another nor his own self is the part of one whose education is already complete.