I cannot tell you how much it bothers me when I open a Word document, and the default font is Calibri. Before I do anything, I change the font to Cambria and breathe easy as I begin my writing. I lean towards the serif fonts, but in some cases, such as on the Internet, sans serif fonts are easier to read.
Take a look at this website that sells font related apparel: fab.com.
What does this say about the rhetorical impact of design on people?