I had a booth at Penn State festival years ago-mid 90's. In the heat of one day a guy came up the road stopping at potter's booths. He was carrying a bucket of water. He stopped at every potter, talked to the potter and then poured water into the teapots the potter had. He did this often enough that I had plenty of warning before he got to my booth. He was very nice, we chatted a while, and he told me he was buying a teapot or two, and wanted pots that poured well felt good, and were nicely finished. He asked if he could check out my teapots, as I had about 8 on display. Each one he poured from, making comments etc. He had a crowd behind him, really creating a scene in a lot of ways on a busy Friday. After pouring and perusing, without a word he bought three-the first three he had bought that day. He emptied his bucket, packed a pot in it, and carried the others in the bag I provided. Lucky me! The rest of that day all of my tea pots were sold. Science yes, luck even better, and I check everyone I ever sell to make certain it pours well, feels good, lid stays on, and the handle works. After a while it becomes second nature. However, every time I set out to do teapots it is a new challenge as it is usually only a few months of the year I do them.