1. Every time I open the Rock, I'm expecting to see my quests come up, not the skill I'm learning. It seems more logical to me that people want to check quests more often than skills, or at least have it open to what you looked at last.
2. Inventory size/too many tools. Don't have a problem with limited inventory, but because of the fact that you need a different tool for so many things, I've found myself staying away from learning new skills if I need a new tool for it. I don't like spending all my currants on more containers to put all the stuff in, I'd rather spend it on something fun.
3. Midlife crisis. Where I am now at level 13, the new skills I have to learn don't have a foreseeable benefit and the enthusiasm kind of stalls. Much like 6th grade. All I can gather is that at one point I guess I'll be able to make my own tools and other items, but for now all I'm doing is collecting more and more stuff that fills up my pack.
That's my 2ยข, wonder what others think.