That’s a pretty invasive question to ask a stranger though. I don’t like to share my thoughts with strangers, as they are much too personal. Someone asks me what I’m thinking lately, and I immediately have to deflect or think of lies to tell in order to not have to say what I’ve been thinking. I don’t want to stand there lying or telling the truth. Much easier to talk about something that isn’t so personal.
I appreciate it's open ended, and one can answer however they please. But faced with this question, I can honestly say I would have to lie. It's like answering the question "How's it going?" with "fine, how about you?" Sure, one can go into how it's really going with a stranger, or they can just respond with pleasantries and small talk.
So if you want to get deep into a conversation with someone about what they've really been thinking about lately, it's not going to happen as a repones to this conversation starter. At best, I think this kind of conversation starter is so open-ended, it's on par with "what's up?"
