A Single Tear is a cliché that generally occurs when a Mary Sue angsts. It is meant to be a more dignified way of showing sadness than full-on sobbing, which tends to leave characters with unattractive red and puffy eyes. Often, it is described with very urple prose, something along the lines of "a pearl-like drop trickled down her silky cheek."[1] When a male character does it, it may be a Manly Tear, because man's man manly men are obviously too full of testosterone and y-chromosomes to outright cry.