I had many contenders for "worst hike ever" until I hiked the Manitou Incline. This is it. This is the worst.
Hooboy. The Manitou Incline is a former cable car track that for some reason people turned into a hiking trail. It's a little under a mile long, but has an elevation gain of 2,000 feet. The Incline is 2,744 steps, and I almost turned back several times. To make it worse, there's a false summit that gives you hope, but once you reach it, you still have 300 steps to go until you get to the real end of the trail. After the Incline ended we took Barr Trail back down to the car, for a total of 3.6 miles. I'm glad I did it and I'm glad I will never ever do it again.
Check out this sweet elevation chart I got from FindHikingTrails.com: