Too many to mention, but here are a few:
Setting off from Stella Point in the knowledge that I was going to make it to Uhuru Peak prompted me to burst into tears. An amazing and unexpected personal experience - I hope no one saw me.
The camaraderie with guides and fellow trekkers. Personal bonds made for life.
So much laughter, especially in times of despair.
Getting to the top of the Barranco Wall and, of course, Uhuru Peak - a truly spiritual moment.
First of all read Henry Stedman's book. That's the only guidebook you'll need.
Take wet wipes.
Plenty of hiking before you go with a heavy load. I hiked 250 miles during the 5 months leading up to the trip.
Take something to wee in at night time - you really won't want to leave your tent at night.
Hire their mats.
Take all the time you need and be positive and remember to laugh and laugh.
Talk to the guides and porters, they are such wonderful people.
The only time I got blisters was on the way down - that day and a half of descent was an unexpected torture.