snag can mean a variety of things. it can be an adjective to describe the good and bad, pretty and ugly, tall and short, big and small... It can also be used as a verb to be either a scandelous, fun, crazy or cool action. It can be used as a noun rarely but it is so powerful that you can just point to someone and name them "snag" or "nada snag". The most important way to use the word snag is to put the right inflection on it.
The most snaggy song out there today is Lady Gaga's Love Game. the most snaggy person is Gilly, as played by Kristen Wiig on SNL.
the most common phrase which involves snag is this: