Want to be happy, do all (or at least some)

Want to be happy, do all (or at least some) of these things today and everyday:

Love as if you will live forever.
Work as if you have no need for money.

Dream as if no one can say no.
Have fun as if you never have to grow up.

Sing as if no one else is listening.
Care as if everything depends on your caring.

…and raise a banner where a banner never flew.

If not now, when?