Originally Posted by ensign_lee

When you don't hit that A or K, you're reduced to bluffing. And normally, that means close to a pot sized bet. So let's say the pot is $40. You each put in $20 preflop (assuming one opponent). Now you're going to bet $40 more to try to win that $40, but only $20 of that is NOT originally yours.

So to sum up, you're betting $60 to win $20. And this will not work anywhere near enough times to show you a profit (It will have to work 4 out of 5 times in order for this play to be profitable).