1. Sweat.
2. Walking.
3. Hills.
4. Precipitation.
5. Racks, draws, ropes, water, and other heavy items in backpacks.
6. Wet talus.
7. Loose talus.
8. Any talus.
9. Bulky pads made more awkward with backpacks stuffed in them.
10. I happened to sprain my ankle on an approach yesterday.

But I love climbing rocks, so a little walking, sweating, gear carrying, ankle rolling, and wet talus hopping are worth it.