I've spent my entire adult life moving gradually west. Much further west, and I'll fall in the water, in fact.
I'm not sure why, either.
Looking at it, I'd be hard pressed to give an answer--any more than a salmon can explain its spawning behavior. While I'd like to think I'm a bit smarter than the average salmon, sometimes I've very little evidence to back that up.
We all do those things, though, don't we--things we can look at later, and exclaim about, when we see a pattern?
There are the obvious human physical motivators driving us all the time, of course: food, shelter, sex, pain. Then, though, there are also the invisible, non-physical motivators: honor, faith, superstition, sex, or fear.
The older I get, the harder a time I have separating those spheres from each other, in my version of reality.