Let's do it vs I'm afraid

Some examples from the web:

• No probs. Let's do it.
• Let's do it together, and take it like a real man.
• Let's do it like Baghdad, baby.
• Let's do it this way, the first to find Mi Reu immediate update.
• Let's do it outside, in nature.
• Okay, dinner. Let's do it.
• Let's do it before Froggy gels home.
• Let's do it together on the count of three.
• - Let's do it, you and me.
• Let's do it like we did it on our wedding night.
• Let's do it now before the kids wake up and then they wonder where we are.
• So we thought, why not? Let's do it.
• Let's do it in the morning before the cops come on duty.
• Let's do it here, by the sea.
• Let's do it that way.
• Let's do it this way, since you brought it.
• Let's do it like Vietnam for Americans
• Let's do it out here in the open.
• Let's do it, boys, why not?
• Let's do it - right here, right now.

Some examples from the web:

• I'm afraid our communication is strictly one-way.
• I'm afraid troubles always find people.
• No, I'm afraid not.
• I'm afraid they're otherwise engaged.
• I'm afraid the company requires a substantial cash deposit.
• I'm afraid we have slightly worse news here.
• I'm afraid you've made a critical error.
• I'm afraid Professor Dumbledore is not here.
• I'm afraid there're ways that he can return.
• I'm afraid I have to take you into custody.
• I'm afraid the situation at the airport has taken an unexpected turn.
• Dad, I'm afraid you're not okay.
• Everything matters, I'm afraid.
• I'm afraid you're misreading the climate.
• I'm afraid that distinction doesn't mean much these days.
• I'm afraid a kidney stone isn't the problem.
• I'm afraid we cannot escape the acquaintance now.
• I'm afraid for my husband's life.
• I'm afraid you've caught me snooping.
• I'm afraid war is inevitable.