It's up to you.

A: What would you like for dinner tonight?

B: I'm not sure. What do you want?

A: It's up to you. Whatever you want, we will have.

 In your dreams!

A: Guess what? This weekend, I caught a fish this big.

B: No way.

A: Yeah, it was huge!

B: In your dreams! It's impossible that you caught a fish that big.

 Play it by ear.

A: Hey, what do you want to do this weekend?

B: I don't know. Maybe we can go to see a movie or have dinner. Why don't we play it by ear?

A: Sure. Let's decide as we go along.

 Keep my fingers crossed.

A; Hey, How are you?

B: Hey, I am doing great. I did well in a job interview yesterday. I really hope to get the job.

A: Oh, have you heard back from them?

B: No, not yet. But I'm keeping my fingers crossed. Hopefully they'll ca11 me today.

Miss the point

A: Okay. So now do you understand?

B: I'm not sure. Can you explain it again? I think I missed the point.

A:. All right. I'll explain it one more time.