Unofficial Geology Law #1
Topography doesn't happen for nothing.
Mountains are mountains because they were thrust up in an orogeny, or because they're made of crazy-tough rock that can't be eroded down, or because they are in fact volcanoes.
Rivers twist because they chip off parts of their outer banks, or because the underlying rocks suddenly fault and jog sideways, or because off to one side there's a super-soft rock type that just loves to erode.
Topography happens for a reason.
Here are just a few of my favorite examples:
Soft Rock vs. Hard Rock
Another (really cool) example:
Fractures Controlling a River