Sometimes, someone will threaten to punch you in the face when you have upset them to some degree. This is considered, amongst the lower primates (see bro), to be one of the best ways to win an argument. Typically, the implication is that, by punching you in the face, the "victor" would be
vindicated. Also, this often implies that you are a
gigantic faggot... as opposed to the guy punching you... who is always
totally straight.
Beware those who actually WILL punch you in the face rather than just threaten to do so. They can often be identified by the imprints of some guy's teeth on their knuckles.