Keep lighter, less necessary questions out of serious conversation unless you want your S. to think you don't care about the topic at hand.
If they're already deep into a topic, don't interrupt it with something else. A few drinks can really help liberate you to say things you otherwise might not say.
Although interesting questions can be a fun jumping-off point, it's not always the right time to engage in lighthearted conversation.
If you guys are already addressing questions important to your relationship, it's not a fantastic time to throw a hypothetical in there.
What about repeat offenders when it comes to robbery, sexual assault etc.? If you could have only one of these three things, a smart phone, a car, or a house which would you choose and why? If your life was made into a movie what genre would it fit in and what actor/actress would play you? Do you play the lottery and what would you do if you won a large jackpot? Have you ever done something to a friend that you regret doing?