Erik Spiekermann, who has crafted dozens of version of the alphabet for companies and cities, believes typeface designers have an obligation to craft letters that are not just pretty but practical, too.

“User interface designers must forget their vanity…don’t forget you’re running a service. You are supposed to design something for other people, not yourself or your mother” said Spiekermann, at Gigaom’s Roadmap conference in San Francisco on Tuesday.

His observation was partially an elaboration of an observation he made this summer, when he described Apple’s(s appl) choice of Helvetica Neue Light for its iOS 7 interface as a “youthful folly.”

Speaking with Adobe Products VP, Jeff Veen, Spiekermann likened Apple’s designers to a group of young students from the same school who become so enraptured with a particular typeface (in this case Helvetica Neue), that they forget the practical aspects of what they do.

“You have to be modest,” he…