Climbing Half Dome was easily the biggest adrenaline rush I had during my time in Yosemite National Park. I was fortunate enough to get lottery passes to do Half Dome after applying only a day or so before!
We got up at about 3 AM to get the initial miles to the base of the climb done by sunrise, and we were definitely rewarded with a beautiful sunrise that day.
Walking up the side of Half Dome is no joke, I'd like to say I challenge myself but this was one of the few times I almost turned around. As you're going up, not only is the gradient close to 80% at times, your left and right drops off very quickly.
We had tape around our hands to help our grip and prevent blistering. The view was incredible as well!
Here's a view from the base of Half Dome to give a sense of the incline.