Sometimes I see a cool looking handmade mug or cup, pick it up and hold it.....then it is not right. Pieces made to interact with the body just have to feel right. A necklace that looks awesome but you just can't wear it because it is uncomfortable just won't be worn. Makers take this into consideration. Mugs, jewelry, cups, pieces meant to be used have dozens of little nuances that interact with the user.
These little DESIGN decisions that the crafts person decides on can make or break a piece. Being a potter the only piece I create that does not bother me if a customer does not like it is a mug or cup. If they pick it up after liking how it looks either they will love how it feels or they won't. Just because I like the feel and the handle of my mug in my hand does not mean every person will interact with it the same. I say mugs are very personal. This usually gets a funny look from a customer and then they go, "Ya, you are right". They realized a big deciding factor to buy the mug was how it felt in their hand. It is a fun little experiment to watch.
So why stress my point about design? I think the best people to design ware that interacts with the user is the maker. The craft artist (if they make functional ware) knows the material and knows how it interacts with the user. Yes, there is thought behind making something functional! Something to think about the next time you are looking at handmade items. Enjoy!