[Alpo]

When you shoot standing, your whole body takes the recoil. You roll with it, pivoting on your ankles. Since your entire (in my case) 200 pounds is being moved, you feel X-amount of recoil

If you are sitting or kneeling, your body pivots at the waist, only half of your body is taking the recoil, so 100 pounds is being moved. This results in you feeling Y-amount of recoil, which is more than X.

If you are shooting prone, your body does not pivot at all, and all of the recoil of the gun is absorbed by your shoulder. This is Z-amount, which is more than Y and a lot more than X.

So there is your trade-off. Standing kicks the least, but because you are just standing there unsupported on your wavering ankles, it is the least steady and most potentially inaccurate position. Prone is the steadiest and most potentially accurate position, but has the most recoil.