Rifles, I had a Winchester 70 SS .375 H&H that would make my eyes water. Traded it for a one pound lighter Rem 700 SS in 375 H&H and it hurt slightly less. Guess it fit me better, but got rid of it too. Strangely, I had a Win 70 .338 prior to that and the recoil bothered me none.
Shotguns, I've shot hundreds and hundreds of 12 gauge slugs thru everything form lightweight single shots to my 870 pump, but they didn't hold a candle to a 10 gauge 36" barrel H&R single shot that I owned briefly. Ran a box of 3 1/2" magnums and one box of slugs through it. Always had wanted a 10 gauge.. til I tried one. And I really wanted to shoot one deer with it, but with 2 1/2 foot groups at 50 yards, it wasn't going to happen. (And I wasn't flinching when I shot that group.)
Worst of the worst, a S&W scandium 360 using .357 magnums. Closest sensation I imagine would be holding out your hand and letting someone smack you as hard as possible with a ping pong paddle. After a little experience, I'd wrap my thumb in black electric tape prior to firing because on the first shot the cylinder latch would remove a chunk of skin from the inside of my thumb! Sold it. After 12 years, I recently bought a scandium 340. 11.5 ounces. Really wanted a snubby revolver again, but didn't want any more weight than necessary. Haven't had time to shoot it yet, but will probably stick to .38's when I do.
