Well, your whole premise sort of goes against traditional customs regarding interviewing. I mean, normally, an interviewer knows who they're going to interview beforehand, giving them time to think of important questions and to research the individual. But if you're just interviewing "interesting strangers [you] come across in [your] everyday life", then you're not going to have that time. So, really, there is no better way to come up with questions with the style you've adopted.
Just take notes of what you find important or interesting. Paraphrase and summarize key points.
And always (can't stress this enough) ask if it's okay for you to record the conversation.
Wait, I think everyone's missing the point here. Or I'm missing the point here. Did anyone think Wario was going to have a sex change? Were these "rumors" ever floating about? Is there a reason this series of words fell out of Mr. McHale's mouth? If not, we should all be much more offended by his audacious misuse of the human brain.
Bioshock: Infinite for me. I was so excited at the start of that game, and the opening sequence was really phenomenal. But I think I experienced the same thing you did with Singularity and just got worn out by the third hour. Really, that game just became a downhill slope after the lighthouse bit.
Skyrim, too. Or maybe that was more of a slow burn. I made the arguably foolish decision to not use the quick travel system to get truly "immersed" in the world. Well, as it turns out, you see a lot of that world pretty quick. Still spent like 40 hours in Skyrim, but it left a really bad taste in my mouth.