I don't really agree with the first myth. Yes sitting on the floor performing hundreds of crunches a day isn't going to produce a six pack, and I do agree that diet truly is the key to seeing your abs. But ask most fitness athletes whether bodybuilder, power lifter, etc and they will agree that abdominal exercise should be performed to keep a strong core. Dead lifts and squats alone in my opinion don't fire the abdominal nearly as much as say cable crunches or leg raises.