An investigator starts research in a new field with faith, a foggy idea, and a few wild experiments. Eventually the interplay of negative and positive results guides the work. By the time the research is completed, he or she knows how it should have been started and conducted.
What turned me on then, and turns me on even today - and when the time comes from me to retire from management I think I'd still be interested in it - is that everything that happens in the world affects the price of securities.