Over the hill refers to being old or someone who thinks in an old fashioned way. Well if they're over the hill then who's under the hill wouldn't it just be easier to go around the hill or maybe just turn around and go the opposite direction of veil but then you'd be going back but if you're on the hill then it's all downhill from there if you're under the hill well it's going to be tough you might have to dig your way out if you just save time you could take the train it goes directly around the hill I like to take the scenic route on the Amtrak it goes under around and then over and then back around and then the way I wanted to go:-):-):-):-):-):-):-):-):-):-):-)