Reflection
You do not owe long explanations when you need space. Short boundary phrases let you state a limit plainly and move on, which preserves energy and reduces churn in social moments.
Keep wording concise and neutral: "I can't right now," "Not able to take this on," or "I need some time to think." Say them with an even tone, avoid over-apologising, and offer a brief alternative only if you want to.
Practice privately and in low-stakes situations: pick two phrases, rehearse them once or twice, and use them mindfully. Repetition makes them feel natural and helps protect your time without creating extra emotional work.