popper says

...I think there is only one way to science - or to philosophy for that matter; to meet a problem, to see its beauty and fall in love with it; to get married to it, and to live with it happily, till death do ye part - unless you should meet another and even more fascinating problem, or unless indeed you should obtain a solution. But even if you do obtain a solution you may then discover to your delight, the existence of a whole family of enchanting though perhaps difficult problem children for whose welfare you may work, with a purpose to the end of your days.