The idiom "hit the nail on the head" means to make an accurate or precise statement, to describe something exactly as it is. It can also mean to solve a problem or perform a task very well.

"What are you up to?" is an idiomatic expression used to ask someone about their plans, activities, or intentions for the near future. It can also be used to express curiosity or concern about someone's actions or motivations.

The idiom "count chickens" means to rely too heavily on something that may not happen or to make plans based on uncertain circumstances. It is often used to caution someone against making decisions without considering all possible outcomes and the potential risks involved.

The idiom "pour cold water on" means to ruin someone's plans or destroy their mood by introducing an unpleasant or unwanted element into the situation. It is used to express disappointment, frustration, or a desire for something more positive or agreeable.

The idiom "rocket science" is used to describe a subject or task that is extremely complex and difficult to understand, especially for someone who is not an expert in the field.