I think I'm more wrathful than sadistic since I never really set out to hurt something so much as kill it. Sure, I do (try to) arrange for some creatures to die some very painful deaths, but my priority is always to ensure their deaths. If you gave me an option that made them suffer but did nothing towards killing them, I would not take it. When I mass pit goblins, I do not drop them 1 z-level onto featherwood floors; I drop them dozens of z-levels onto menacing spikes! When I have my way, every uncaptured goblin is ripped to shreds by weapon traps all made from masterwork mechanisms and loaded with 10 masterwork adamantine large serrated discs each, and every captured goblin falls at least 30 z-levels onto 10 masterwork adamantine menacing spikes surrounded by magma which will disintegrate their corpses before there is any need to clean them up. The end product of my work will always be dead goblins; maimed and crippled goblins are produced only as intermediate steps to dead goblins.
Giant sponge shows up in my river, potentially blocking other, more interesting animals? I'll build a pair of towers to support a bridge 18 z-levels above him from which I will drop cinnabar boulders on that waste of flesh.
A useless and possibly dangerous animal wanders onto the map instead of a useful one? My military, armed with only masterworks, will kill it. They might kill it before it gets caged, or they might kill after it gets caged as a training exercise, but they will kill it (unless they die of old age first). Any useful animal who kills a fortress member will also be killed.....though in most cases, it only ends up being killed sooner than it would have been killed otherwise.
I use bone bolts for hunting to conserve metal, and am annoyed at how long it takes for my hunters to kill most animals. I think I'll try to figure out how to mod bones so that bone bolts are more lethal against unarmored targets but not armored ones.
Even though some of the more painful ways to die amuse me more, I don't really want things to suffer for the sake of suffering, I just want things to die.