i've done that to myself 100s of times. I mess up once and I say "oh, what the hell" and eat the entire cake. I not only feel guilty, but the carb/sugar overload literally makes me sick. And I've gained 5 pounds the next day. Now I look at a cheat as something totally not worth doing. Sure it may taste good momentarily, but it is not worth sacraficing an entire week's worth of dieting.