Hmmm... favorite place? This one is tough. But I guess I would say Everest Base Camp. Viewing Mt. Everest from just a few miles away is truly awesome -- esp. at sunset.
Least favorite? I would say most of the temples in China. The very sad thing is that most all of them were destroyed during the 1960's Cultural Revolution. Those with high tourism value have since been rebuilt -- made to look old -- some actually quite nicely done --but sadly -- the ubiquitous ticket booths, uniformed temple attendants selling incense, and the generally sparse worshipers all made for an antiseptic, outdoor museum feel.
Biggest surprise? Just how EASY it was to get up to Everest Base Camp. On the Nepal side, I understand one has to trek for days. But on the Chinese side, they drive you right to your tent if you wish (and most everyone took up that offer). I and a small handful of others got out of our vehicles and hiked up the last 2 miles or so -- and I was glad I at least did that. Elevation - 17,200'.
(1) Most humans are pretty darn decent. Every time I needed help (e.g. language barrier, logistics, etc.) -- somehow, help was always forthcoming. Indeed, on this and other past trips, the kindness of strangers have always been a highlight.
(2) This was my first long trip (7 months). I like how this trip made me much more open, flexible and tolerant of different peoples, conditions, situations, etc. After months of constant 'on the go', I got to the point where I didn't care at all where I was or where I would be heading next. "Home" was wherever I was at each particular moment. I was happy to return to my real home toward the end, but would have been equally happy to continue on. I like that feeling of not being emotionally tied to any one place any longer.
Since my trip was mostly hosteling, TP was always available -- although mostly the coarse brown type in the former USSR and Mongolia. China, OTOH, was much, much more advanced in terms of infrastructure and consumer goods.
Finally, re. water -- I tend to combine bleach with my Aquamira filter when hiking. However, as stated, this trip was hosteling -- and I brought along my Steripen Adventurer. The Steripen performed marvelously all through the 7 months of regular use. I went through 3 sets of CR123 batteries -- which weighed almost nothing and took up almost no space. My Nalgene bottle and Steripen saved me a ton of money -- and were good for the environment. Never got sick the entire trip.