Of course I like the rush of a barely controlled descent down a mountainside. But roots and grabbing mud that'd sling you off the hillside if it could. The first thing I noticed is there's nowhere to go but down the trail and the trail is riddled with roots, stumps, rocks, mud, and generally uneven terrain. Braking only makes an enemy of your bike, so really there's nowhere to go but down the trail at the speed it wants to have you. What you have to do is reach far with your gaze and plan a sequence of fine shifts in balance to course that front wheel through the hazards and counterbalance back-end skids.
Momentary relief is found at sporadic level and dry spots where it's safe to brake a little.
Once the rush is over, you're hauling your ass and the bike up a trail, pedaling in amazingly low gears like I've never had the pleasure to try. Even in the granny gears, your heart's leaping through your ribs and your breath embarrassingly loud as you take rocks, roots, and mud in the opposite direction. I never expected to enjoy myself like I did.