At one time, waaaaay back when, there weren’t any cell phones nor answering machines and we actually spoke to each other on a land line telephone. So, if you had a question about a tone, inflection or the like, you could actually, instantly find out the meaning.

And this is also why some of us actually look around when we’re walking. (Aside from missing your destination, it prevents us from walking against red lights, tripping over objects. Basically by looking around, you can reduce the number of doctor visits due to accidents from not paying attention.)