Beating a dead horse? Never heard of it. Some things are worth letting go—this isn't one of them. Call it persistence, call it stubbornness, call it whatever you want, but giving up? Not in the vocabulary. If there's a hill, this one's dying on it. If there's an argument, it's getting rehashed one more time. Is it over the top? Maybe. But if flogging the same old thing was a sport, this one's taking home the gold. Quit? Neigh-ver.
