There's a certain pace to conversations, and it's tempting to fall in with it.
But when you're speaking with someone insightful, inevitably you'll hear something that's more insightful -- and requires more thinking to fully process.
Being able to slow down and just think it through, patiently, is key. The common reaction you'll get is something like, "Does that make sense?"
But simply replying back, "I'm processing... I'm thinking that through..." both shows a lot of respect for whoever you're listening to, and gives you time to really think about how what you heard applies to your life.
Don't feel the need to reply so fast. Great ideas need the implications thought through.