I'm kind of speed obsessed, so I go uphill and downhill both as fast as possible. Uphill, I maybe gear down one notch from my flatland gear and mash my way up, standing if I have to. Often pass a few low-gear spinners on the way up. Downhill, I tuck and coast, hands close to the brakes. On one particular long, gradual downhill, I'll pop into the big ring/small cog, and pedal to try to keep up with traffic. It's one hill where I'm almost as exhausted when I get to the bottom as I get when climbing to the top.