That's a way to increase the realism to the reader, if you want to get technical - you leave it [character] vague and you let the reader fill in the blanks with their imagination.
Nicholas SparksBelieve me, I'm no romantic, and while I've heard all about love at first sight, I've never believed in it, and I still don't. But even so, there was something there, something recognizably real, and I couldn't look away.
Nicholas Sparks