1. Numb toes. I can't feel either of my big toes. Informal survey suggests that neither can about 75% of other hikers. I also have no feeling in my left arm from my shoulder to my elbow.
2. Going down is harder than going up. A steep downhill is physically more difficult, more painful and more mentally taxing than a steep uphill and the probability of injury is much higher.
3. Going "fast" on the AT has way less to do with hiking speed than it does with number of hours hiked. I'm keeping up with much faster people just by getting up early, hiking later in the day, and not taking many days off.
4. We thru hikers can smell your laundry detergent. And your deodorant. And if you have on perfume, we can smell you coming from a mile away. I don't know why, but somehow the fact that we haven't showered in a week makes us super sensitive to people that don't smell like us.
5. Singing out loud off key while walking in the woods by yourself is amazingly therapeutic. Until you're busted by a day hiker. Then it's amazingly embarrassing. But not so embarrassing that you don't start singing again about a hundred yards past said day hiker.
6. Walking in the rain isn't that bad. As long as you take your shoes off every few hours and let your feet dry out, you don't get blisters. I'd almost rather walk in rain than scorched by sun!
7. Being above treeline never stops being amazing. Whether you're socked in with clouds or can see for miles, it's magic. Pure. Magic.