[krenoten]

It's important to have some way of distinguishing "problems" from things you have no control over, also. Some things you have to accept, which sometimes boils down to locating an incorrect assumption that you have about the world and invalidating it to yourself. You get to choose what you spend energy on, though.

[andyzweb]

    accept the things I cannot change,
    the courage to change the things I can,
    and wisdom to know the difference.