I'm not sure about this. One of my favorite tools is my bicycle. To me, the user interface of my bicycle is totally invisible. I just pull it out of the garage

I'm not sure about this. One of my favorite tools is my bicycle. To me, the user interface of my bicycle is totally invisible. I just pull it out of the garage, hop on, and away I go. And it's not like I enjoy my bicycle as a "puzzle" either -- I just want it to go somewhere. But to my 6 year old, the user interface is quite literally fear-inducing. Everything about the tool is very "visible" to him. Does that make it a bad tool?