What's the worst/most difficult hike you've ever had?

Most difficult doesn't necessarily mean bad.

Mine was the Fiery Gizzard in TN. If you're unfamiliar it's one of the most difficult in the state. A friend of mine called me up one day out of the blue and asked if I'd be up for a hike with him. I was unfamiliar with it, but he said it was only about a five mile hike.

Anyways he picks me up the next day and we drive out to the trailhead. My friend hadnhikednit before about a year before,although when he did, he hadrepared for it for a couple of weeks beforehand and when he hiked it, it was in the fall. I, on the other hand, went into it 'cold' and we did this in the height of the summer heat.

Also, it was five miles to the HALFWAY point. Where we turned around and then started back. Boulder fields, summer heat and humidity. The trail is really gorgeous and I loved the scenery, just that last mile or so before the halfway point was sheer up a mountainside. We were heaving and sweating our asses off. It was dark by the time we got back, and I had crazy blisters for a week.

I still enjoyed the experience, but man I could have used a bit of a warm up to it.

Anyone else? Have some particularly arduous, bad hiking experiences?