Duty and desire are different things, and yet so closely related.
Both can be many things, hundreds and thousands.
Different for each person, although there may be things in common.
Duty is what we are required to do, what is our 'obligation'. There may or may not be a deadline. It may or may not be imposed by others. But whatever it is, it must be done.
Does it have to be productive? Does it have to be relevant? Does it have to be special? That duty could be a promise you made to a friend to play video games. It could be homework for an unimportant subject. It could be sweeping your room.
They are simple or complex tasks, which you may or may not like. But they are necessary to live. To be able to be.
It doesn't matter what it is, what matters is that it is. Without it, we would have no foundation on which to stand. That which sustains us.
Desire, on the other hand, isn't something we have to do because it's our obligation; it's the opposite, it's something we have to do because it's our passion.
We aren't obligated to do it, and yet we choose to put effort into it. We choose to postpone our duty. We choose to put it above the demands of others. Because it's personal, individual.
There is no greater goal than the one you set for yourself, except for the goal of living. And at the same time, living is achieving your greatest goal.
Such opposite, separate poles that unite in life to form a beautiful cycle.
To live is to desire,
to desire is to must,
and to must is to live.
That's why I must desire you so that I can live.