Are ideas interesting, or are they true?
From an NYT Magazine article this Sunday, paraphrasing Isaiah Berlin:
The philosopher Isaiah Berlin once said that the trouble with academics and commentators is that they care more about whether ideas are interesting than whether they are true. Politicians live by ideas just as much as professional thinkers do, but they can’t afford the luxury of entertaining ideas that are merely interesting. They have to work with the small number of ideas that happen to be true and the even smaller number that happen to be applicable to real life. In academic life, false ideas are merely false and useless ones can be fun to play with. In political life, false ideas can ruin the lives of millions and useless ones can waste precious resources. An intellectual’s responsibility for his ideas is to follow their consequences wherever they may lead. A politician’s responsibility is to master those consequences and prevent them from doing harm.
I can't speak for that level of politics, but I've seen in applied technology the distinction between interesting and true ideas can be great. (True in the sense of, it is true that the idea solves the problem at hand.) I've wasted plenty of time recently at work chasing down very interesting ideas only to reassess and do something more expedient. A different example from empirical science: it sure sounds interesting when the 1950's Chomsky claims that language can't be statistically modelled, though that turns out to be embarrassingly false.