While some people might want to ask a prospective love interest whether they're a dog or a cat person, or if they prefer ketchup or brown sauce on their sausage butty (dogs and ketchup all the way), others might ask about two other opposing concepts: the rival worlds of Harry Potter and Lord of the Rings.
While both first began as book series, they each went on to become huge franchises, having since spawned countless big-budget films - and even several spin-off movies and TV shows.
Both also focus on the supernatural, with monsters, dragons and magic all part of the fun.
But there's another thing they both share, and that's the inclusion of a friendly, grandfatherly wizard with a long beard - Gandalf in Lord of the Rings and Professor Dumbledore in Harry Potter, obvs.
Where these two roles differ, however, is apparently in their ability to kick ass, as Game of Thrones creator George R.R. Martin believes the wise wizard of Tolkein's fantasy world would win in a fight.
Martin had attended the premiere of the Tolkien biopic on Wednesday in Los Angeles.
Variety reports that after the screening, Lily Collins - who plays Tolkien's wife Edith Bratt in the film - named Harry Potter as her favourite book series.
Martin then reportedly chipped in, saying: "Gandalf could kick Dumbledore's ass."
You can just imagine Gandalf shouting 'YOU SHALL NOT PASSSSSS!' at ol' Dumbledore, before nutting him with his staff. Not that we'd condone that, of course.
I mean, given that Martin is the man behind one of the world's biggest fantasy franchises, I'd be inclined to take his word for it - but then Harry Potter has an entire section of your local Primark dedicated to it, so...
Meanwhile, Game of Thrones has been blowing everyone else out of the water with its high-octane final season - although Martin has admitted he's sad the television adaptation of his work would be coming to an end.
In an interview with Rolling Stone, the 70-year-old said: "You know, it's complex. I'm a little sad, actually. I wish we had a few more seasons. But I understand. Dave and Dan are gonna go on to do other things, and I'm sure some of the actors were signed up for like seven or eight years, and they would like to go on and take other roles. All of that is fair. I'm not angry or anything like that, but there's a little wistfulness in me."
Game of Thrones continues on Sky Atlantic on Monday 13 May at 2am, then repeats at 9pm for viewers in the UK.
Featured Image Credit: New Line Cinema