As usual, accuse the other guy of what you're doing yourself.
There is no shame in this, is there? No embarrassment, no hesitation. It's win at any price, the truth be damned. Any end justifies any means, lie, cheat, whatever, just so as to win.
One doesn't want to believe that of associates, and yet hit us hard enough, long enough, with the same old thing one is left with no choice but to believe that's the kind of people they are and they enjoy it.