It's amazing that Kepler derived his three laws emperically and then Newton rederived them from his own laws of motion. Its conceivable how Kepler derived the first and third laws, but the second law? How would Kepler have measured the area of the arcs swept out in equal time intervals just by looking at the data and why would he have the motivation to do this in the first place?
Kepler analyzed an enormous amount of data provided by Tycho Brahe. The data provided by Tycho Brahe must have represented a monumental effort.
In my opinion, it must have been more grueling for Brahe to collect all the raw data than it was for Kepler to analyze the data. The amount of number crunching Brahe did was staggering.
If you could plot all the data to scale on a sheet of paper and actually see the ellipses and the time lapses between locations, I don't think it was all that much of a leap to see that the longer, narrower slices of pie could possibly equal the areas of the shorter, fatter slices of pie. To me, that's pretty intuitive.
Motivations for finding answers to huge questions of the day? There are at least several: Fame, glory, wealth, prestige, the thrill of being the only person on Earth to know a truth for a short period of time before you publish your results, etc.