If two guys are attempting to mug me while I'm in a phone booth in my hometown (and it's clear that they don't have weapons), then I'm obviously going to use fists.
If some guy is tugging at my wife's shirt in a crowded square in a foreign country, then I don't think fists are warranted, but spit certainly is. She herself was persistently telling him to stop, and he didn't. Thus a "fuck off" from me wasn't necessarily going to get the job done either.