When someone asks you, "What's wrong?" it's essential to respond politely and appropriately, especially if you're not comfortable discussing the issue or if it's a private matter. Here are some polite responses you can use:
"Thank you for asking, but I'm just feeling a bit tired today."
"I appreciate your concern, but I'm dealing with a personal matter right now."
"It's kind of you to ask, but I'm working through some things on my own."
"I'm okay, just having a rough day. Thanks for checking in, though."
"I'm touched that you care, but I prefer not to talk about it at the moment."
"I'm managing, but I'd rather not go into details. I appreciate your understanding."
"There's nothing specific, just some minor things on my mind. I'll be fine."
"I don't want to burden you with my problems, but I appreciate your support."
"It's nice of you to ask, but I'd rather keep it to myself for now."
"I'm okay, really. Let's talk about something else if that's alright with you."
Remember, it's okay not to share personal information if you don't feel comfortable doing so. Polite responses should acknowledge the concern of the person asking while also setting appropriate boundaries. If you feel comfortable discussing the matter, you can share more, but it's entirely up to you how much you choose to disclose.