Reminds me of why torture as a means of information gathering is ridiculous.
I will absolutely tell you what I think you want to hear when you start stabbing me, whether its the truth or I ever knew it at all.
But I also hate you for torturing me, so If I do happen to know the thing then I also know enough about the thing to alter the answer to something false but plausible for a moment of relief while you act on it, because we all know if you're torturing me, you have no intention of letting me out alive.
This is why the lets be pals/wine and dine approach is more effective.
"Thanks for finally providing some info. We are going to go corroborate it. If you lied, or if we can't find convincing evidence your info was right, we will take this conversation up with your wife/kid/family"
This is why I liked the how Torture skill in Burning Wheel does just this: you decide what the victim says. It's not true, it's just what they admit to.
Pain can be efficient or counterproductive depending on the individual. The threat or pain is usually more efficient than the pain itself.
Your "let's be pal" approach is not far from the KUBARK's recommendations, but it is not incompatible with coercitive methods: On the contrary several of these consist in putting the interrogatee in a state where the interrogator is perceived as a reassuring presence.
Reasons why I like systems that have rules for this sort of thing.
"Sure, you can torture the captive. That's a rank 8 check against Violence, so go ahead and roll. Oh, you don't want to risk any mechanical consequences for your horrible actions? Ok then"
I feel like there's a lot of overlap between powergaming min/maxers and war crime doers. It really keeps players in check without having to resort to hand wave-y deus ex machina like "it turns out the bartender is a level 20 barbarian lol"
That's from Unknown Armies (2e). A great game with a great rulebook. It really made me think about some assumptions I'd been making about how games work.