Design is as old as the first tools made by cavemen. Just about any item, be it clothes, tools, architecture or weapons can easily be recognized coming from a specific time, if not a specific place. Times change, and those changes are driven by everything from technological and science advances to aesthetic changes which can be prompted purely by accident. The powdered wig became popular when King Louis XIII began wearing one because he was going bald. Soon, men who weren't losing their hair at all were wearing powdered horse hair wigs, marking them out as coming from a specific age.
Like all other things, automobiles can be pegged as being from a specific era at but a glance. Some of this is driven by brands finding a unique design language. Some of it was driven by advances in technology that pressed certain details into specific shapes. Other changes were the result of safety regulations which forced automakers to include equipment that dictated certain characteristics, or that specific traits of vehicles exist in ways that determine style, like the height of tail lights or the distance between headlights.
If you were to detail all your opinions on cars from a variety of ages, that data could be used to triangulate your taste in cars, but more impressively, it could be used to determine which decade best fits your taste. Take this quiz, and we'll tell you what decade to travel to in your DeLorean.