When the Toyota Prius hybrid became popular in the late 2000s, detractors labeled its angular, cut-off style ugly. In contrast, Motor Trend compared the sleek 2013 Tesla Model S to a "supermodel working a Paris catwalk."
So how can Prius owners drive around with the same degree of pride in their vehicle's awkward design as enthusiasts have for the sleek lines of the Tesla Model S?
As electric and hybrid vehicles drive into the consciousness of mainstream buyers, manufacturers are rethinking conventional approaches to their exteriors. They are discovering that one driver's four-wheeled ugly can serve as another's badge of honor. Long-held assumptions about what buyers want don't necessarily hold up.
The Nissan Leaf is a prime example of the unresolved tension between aesthetics, mass manufacturing and consumer psychology as the electric-car market evolves. When the company announced its plans to make the Leaf (the world's first mass-market electric car) form definitely followed function.
(Read more: Best convertible designs of all time)
For example, the headlamps (which protrude upward and outward) were shaped to reduce wind noise but have become a hallmark of the five-door hatchback's signature look. The car lacks a conventional front-end grille because an electric vehicle doesn't have a large engine and therefore has no excess heat.
"You don't have a grille, because you don't need a grille," said Andy Palmer, Nissan's executive vice president in charge of product planning.
Some design elements are simply for looks, though. Nissan details all its electric vehicles with blue chrome highlights, for instance.
"Carmakers are obsessive about badges, and we are no different," Palmer said.
The blue chrome highlights were a glance in the right direction but still not enough to impress Daniel Sperling, director of the Institute for Transportation Studies at the University of California, Davis, who admits to being put off by the styling of his wife's Nissan Leaf.
"It's not one of the better-looking ones," he said. Sperling said time to market played a role in limiting Nissan's aesthetic choices. "Part of it has to do with the fact that [Nissan CEO] Carlos Ghosn said publicly in 2010 that he wanted an electric car quickly."
Palmer doesn't necessarily disagree. New designs must have global appeal, he said, which is why the Leaf was created as a five-door hatchback. And rather than envisioning a futuristic beauty, he added, "we wanted to make it as inoffensive as possible."
(Read more: How fuel efficiency is changing car design)