Wake the F#CK up w/Jeff #220- why cant you say NO to your dog

I am really trying to understand why folks cannot say NO to their dog. Why do they allow their dog to keep misbehaving, doing dangerous things, and running the household? is it that folks actually think dogs are supposed to be primarily misbehaved? is it a self-esteem issue and you actually can't set down rules and boundaries as you don't think your dog will love you? what is it?