Do what you love doesn’t mean, do what you would like to do most this second. Even Einstein probably had moments when he wanted to have a cup of coffee, but told himself he ought to finish what he was working on first.
The rule about doing what you love assumes a certain length of time. It doesn’t mean, do what will make you happiest this second, but what will make you happiest over some longer period, like a week or a month.
Unproductive pleasures pall eventually. After a while you get tired of lying on the beach. If you want to stay happy, you have to do something.
— From Paul Graham’s essay.