All of the people who know what "GAB" means are completely unanimous in stating categorically and absolutely that we will never reveal or explain what GAB means, even if we are all tortured with the worst hell imaginable for a thousand million years.
I'm not particularly interested, since such text-language is lazy and tedious anywhere other than on a mobile phone, but could it possibly be "Gimme A Break"? Would that fit into the situations where you have seen it?
IndieSinger , how do you know that "Grumble, Argue, Bicker" is not right? Do you know something that I don't? Or do I know something that dysmal and RevShirls don't know? I reckon it's just made up and doesn't mean anything.
By the way, yes smudge I can put you out of your misery but I'm not going to. And nor is anybody else.