One thing I recently realized is that "how much is too much" (regarding side tilt) also depends on what's to your side.
As in, "If the tractor rolled here, what would happen?" - If you're mowing the side a ditch and a rollover would result with the tractor laying on its side on the other side of the ditch, that's not ideal, but it's not particularly terrible. If you're mowing the side of a pond, and a rollover would result in a bath... that's significantly worse, especially if the pond is deep and muddy, your ROPS could sink in significantly with all the weight of the tractor on it. If you're a steep hill and there's no flat spot to turn around at the top (you are mowing up and down the slope, right?) so you've got a brief side-slope as you turn around... a rollover could be over and over and that could get really nasty too.
In my own moment of clarity, I was considering that a rollover (I wasn't at the pucker stage yet but I was like "what if this edge collapsed now?") could get me skewered by a t-post that was to my side and below, or smooshed against a very strong wooden post... think like a tree. ROPS won't help that.
My point is, danger is relative. I'm not suggesting that it's ok to rollover in some situations, but I am saying that I'm willing to push things more in some cases than others.
Think track days. You get on a motorcycle and ride at a track in controlled situations where a crash is most likely going to result in a few scuffs on the protective suit (and there's an ambulance standing by); you're more willing to ride hard there than on the country road, but you still would rather not crash.