Some people have stated that Taking 20 is performing the same action over and over again. While this *could* be possible, I think it is just flavor text and it isn't the only flavor text that is available. You could certainly make your arguement look good by saying "Take 20 on a Hide is equivalent to Hiding behind a bush, coming out from that bush, Hiding behind the bush again, coming out from that bush..." repeat 20 times. Yes, when you think about it this way, then it makes no sense. But the other "arguement" using flavor text is also viable, "I take 2 minutes of my time to locate the best spot to hide. I want to take time to conceal myself well, cover myself with leaves, bend this branch so the leaves are covering my face, make sure none of my appendages are exposed, etc."
We can even apply this to Use Rope, to make Taking 20 with Use Rope seem ridiculous. If you have an unconcious opponent, and want to tie him up, and you are not threatened, distracted, and have 2 minutes of free time to do it, then you can Take 20 on Use Rope to tie them up. Does this mean you tie them up, untie them, tie them up again, untie them, tie them up again... repeat 20 times until you "get it right"? That doesn't seem logical to me. But if you are going to apply the "Hide behind the bush multiple times" arguement to it, then that is what you get. I think it makes more sense that you are taking extra time to make sure the knots are secure, that you've wrapped the rope around the opponent enough times, that you securely bound his hands and feet, etc.