Rather than rehashing, I'll refer the reader to Jami L. Haskell's post in her blog, Librarian Like Me.
The things that really stood out for me were people's reluctance to choose carefully among many choices - they choose the default. How the looks of the scale can influence how people answer questions - visually they interpret the middle of the scale as "normal" even if it isn't (how many times per day do you floss your teeth? 1-10). How we accept physical limitations but expect people to have mental superpowers. To encourage database use, let students know the real cost and that they need to use it or lose it (when the semester or college is over).