To some extent, I like when people do it in other languages. It exhibits strong exposure to older programming material (where overshort vars abound), evincing great passion for programming, computer science etc.

A lot of lisp material features single letter vars, for example. (Actually, var length in prod code bases seems related to scope. So toy examples with obvious context see single letters strewn about. But digging through the classic books will rub off on the budding programmer...