I'm a pretty aggressive guy. Ask me to grab and assuming you aren't a beginner I come in pretty solid. And, I'm stubborn. I've been plowed quite a few times and I often wind up muttering, "I know better".
This is one thing. I did it to myself and falls into the realm of exploring edges.
Inflicting pain is something else entirely. Unless I get stubborn, and or, for some reason resist (usually because the opportunity was given to resist by someone applying technique) when the technique is applied, pain means something is wrong. The descriptions I read above implied to me a situation where pain was applied as part of the technique. To me, applied pain, means a forced expression of technique or dominance. I don't think this is entirely invalid in all situations. If I were in a fight and needed control or in law enforcement I could see this sort of expression of technique. However, I don't believe it's the most effective expression of technique.
For instance, applied pain tends to focus nage on a specific point and is effectively an attack. At this point, you've give me something to work with. I have information that I can use and if I choose to, I'd likely change what I was doing to counter, withdraw, or redirect my attack.
The best throws are those you never feel.