What's up with that? = Why? What do you think of that? How about that?
(This expression is relatively new. Ten years old?)
"The boss says we have to work late tonight. What's up with that? Doesn't he know we have lives after we leave here?"
"Ann is telling everyone she's getting married, but she hasn't invited me to the wedding. I thought we were close friends. What's up with that?"
The blind leading the blind = refers to incompetent leadership/teachers
(Imagine a blind person whose guide is also blind. Do you think it would work out, that it would be a successful relationship? Probably not! I can't play the viola caipira. Can you imagine me trying to teach someone else how to play it? Ridiculous! We use the expression "the blind leading the blind" to refer to incompetent leadership and to incompetent teachers.)
"Did you hear about Charles? He's the new manager of the store, but he's never worked in a store in his life and the other employees are new too. Talk about the blind leading the blind..."
"The new teacher knew nothing about chemistry. It was another case of the blind leading the blind."
To talk apples and oranges = to compare things that are quite different
"Asking me if I prefer eating dinner in a restaurant to going to see a movie is talking apples and oranges. Some restaurants are good and some are bad. Some movies are good and some are bad. One has nothing to do with the other. They are like apples and oranges."
To be up a creek without a paddle = to be in a bad or dangerous position or situation
(Imagine being in a canoe in a stream, and you don't have a paddle. What are you going to do? You're going to be helpless, right?)
"If your girlfriend finds you again with Mary Ann, you're going to be up a creek without a paddle. She's going to kill you. Very slowly."
"It is very important that I get to the appointment on time. If the car runs out of gas 10 kilometers from the meeting, I'm going to be up a creek without a paddle. I'll be in trouble, deep trouble."
"If a bear comes into your tent tonight to eat your food, you're going to be up a creek without a paddle. You had better leave the food outside the tent and far away."
Break a leg! = Good luck!
(This expression began with actors who thought it was bad luck to wish someone good luck. So... they started wishing their friends bad luck hoping it would bring them good luck. Understand? Neither do I.)
"Jack, I so happy to hear about the new job! Break a leg!"
"Sally, I hear you have exams tomorrow. Break a leg!"