in building many products over the years, the best test of how good the interface was, was to put the product into the hands of seniors or young children. Both are excellent test audiences. If it is truly intuitive, the kids pick it up fast. If it is simple and well organized, the seniors will respond. Both groups have different strengths: seniors have no memory, and kids have little abstraction power.

I wish this perspective was more widely held. I think we see a lot of the reverse attitude toward what makes a good design or good software.