You miss the fiber, obviously, and you miss trace amounts of the liquid that remains in the pulp.
As Mark points out - could you have possible eaten 10 carrots? Probably not. IF you can up your ratio through juice to 3 to 1 (you get the nutrition of 3 xyz's through juicing and you would have only been able to take in 1 xyz the 'normal' way) you are way ahead of the game!