I like that you can usually get in close without spooking the fish. It feels like hunting.
So many of those rivers in Colorado and Wyoming you couldn't see the fish in those runs, riffles and eddies. You'd just pick a likely spot and drift a fly through. I'd also let it go through the entire swing and was frequently rewarded for my patience with a fish when the fly finished it's swing across the river.
I hate South Carolina when I'm talking about stuff like this.