C.S. Lewis Advice to Kids

In a letter to a girl named Sarah, dated April 3, 1949, Lewis writes:

Remember that there are only three kinds of things anyone need ever do.

(1) Things we ought to do
(2) Things we've got to do
(3) Things we like doing.

I say this because some people seem to spend so much of their time doing things for none of the three reasons, things like reading books they don't like because other people read them. Things you ought to do are things like doing one's school work or being nice to people. Things one has got to do are things like dressing and undressing, or household shopping. Things one likes doing --- but of course I don't know what you like. Perhaps you'll write and tell me one day.