I'm gonna put this here in Other, because even though I will use Sherlock as an example, this subject is more about acting in general.

This is something I've wondered about for quite a while, and this is the question I would've liked to ask to Ben and Martin if I'd ever had the chance:

How is when what you act with someone is in odds, or even correlate, with your real life relationship with the same person? 

This can go for romantic partners like Martin and Amanda, but also with friends/collegaues like Ben and Martin. Or Martin with the "dwarves" during The Hobbit. When you spend a prolonged time shooting with someone, your relationship with that person is bound to go up and down. One night you might have gone out to the pub with your co-star, sharing a beer and two and everything is great. But then the next day perhaps you're supposed to shoot a scene where you're really angry with each other - but in real life you're really in a good place.

Or the other way around. For whatever reason, this week this person is really annoying you, but you have to shoot some fluffy and friendly scene with them. Or the worst one: You are quarreling over something in real life, and you're shooting a scene where you're quarreling in the movie/series. How do you prevent real life from bleeding into the shoot?

I know that the answer will mostly be "But they're professionals". Yes, they are. But they are also human beings, and they feel love, warmth, annoyance and anger just like the rest of us. So what do you do? Do you use those real-life emotions in the scene? Or is that too close to home, so you keep a professional distance, creating your on-shoot emotions from somewhere else?

The only thing I've seen that deals with this from the cast of Sherlock is Amanda. I just saw an interview where she mentioned shooting the HLV scenes with Martin, and saying that she hoped she would never live through that in real life, Martin looking at her like that. (Paraphrasing). Which I think just makes this issue more interesting. We all know that a life-long partnership can be in a good, neutral or bad place. How to act together depending on the dynamic in your real-life relatinoship that day? 

I just think this is an interesting topic. What about you guys?