What I've learned...
1.) No matter how many times I've done a hike, I will reread the trail description in the AMC Guide. As you've probably read, I fell through ice on a brook crossing I could easily have avoided. The fifth line of the trail description warned about the crossing and how easy it was to get around.
2.) We almost always hike in just our group of my wife, dog and I. I have pushed my wife on a couple of times when I probably shouldn't have. When conditions aren't ideal, or if one of us is having trouble, we should all turn back. We have turned back because of conditions twice and because of my "swim" once. This rule probably won't apply to many other groups, but it will to ours from now on. The mountains will still be there the next time.
3.) I lost a water bottle, someone returned it by mailing it and wanted no remuneration. My wife lost a camera, people behind us on the trail found it and returned it in the parking lot. I found a water bottle and returned it in the mail, so I was able to pass on the kindness. Today my wife found a camera and it turned out to be someone in our group who didn't know he had lost it. Make sure everything is stowed away properly! If you do find something, post it on a hiking forum. It's possible you can find the owner, I did. You never know when you might lose something and your kindness may be returned.
4.) Enjoy the hike. Take in the beautiful surroundings, the sky, the snow covered trees, the brooks. Enjoy the hike for what it is. Don't be so hell-bent on reaching the summit that the trip isn't enjoyable. Sure, most of us have lists we want to complete, but is that why we're out there?
OK, I'll stop. I'm sure I learned more, but you've probably forgotten more than I'll ever know!
KDT