When I was considering what to name "bulbs" (http://bulbflow.com), the round corners of the letters was one of the factors. For example, I think the round letters in google and apple help give the brands a soothing feel.

Likewise, I think the soft edges in the python and ruby syntax are more pleasant, and I find it irritating to switch between python and sharp-edged languages such as JavaScript }{ -- this may be one of the reasons lisp is so beloved :)