Stealing Someone's Thunder, Hitting the Sack, Hitting the Hay, Digging Deep, Cheesy

Stealing Someone's Thunder
To "steal someone's thunder" is an expression for taking the credit and praise for something someone else did. That is, someone else does the work, but you take the credit.
Ex.: "Brian worked for a whole week on that project, but Dave acted like it was all his doing. You shouldn't go stealing someone else's thunder like that." Dave took credit for Brian's hard work.

In the movie "Percy Jackson & The Olympians: The Lightning Thief," a character steals the thunderbolt of the ancient Greek god, Zeus. While fiction, this would be stealing someone's thunder figuratively and literally.


Hitting the Sack
As detailed in "hitting the hay," sacks filled with hay were once used as mattresses in the United States. Thus, the expression "hitting the hay" came into wide use as a metaphor for going to bed and going to sleep.
Ex.: "I'll hit the sack after I finish watching Jay Leno." (Jay Leno's comedy show is a late night television program, so anyone watching it is automatically up late to begin with.)


Hitting the Hay
Hitting the hay is an expression for going to sleep. Even when a far greater percentage of English-speaking society lived on a farm, humans did not actually sleep on hay itself; hay is made of straw, and straw prickles. Many domesticated animals, however, can sleep on hay just fine. More importantly, hay stuffed in sacks was often used as mattresses in the United States at the start of the 20th century (circa 1900). Thus, hitting the hay became an idiom for laying down on one's bed and going to sleep.
Ex.: "I'm going to hit the hay right after making this last blog post..." This means, I will go to sleep after making this last blog post.


Digging Deep
Figuratively speaking, "digging" is searching, even if it has nothing to do with physical soil. "Digging deep" means to spend a great deal of effort searching for something.
Ex.: "I had to dig deep to find the answer to question #5 on the exam. It was a tough one!" The speaker had to explore his or her own mind deeply to find the answer.


Cheesy
Literally, something is cheesy when it has a great deal of cheese - a tasty, but fattening food - on top of it. Figuratively, something is cheesy when it has a great deal of emotional exploitation and little substance.
Ex.: "Teen romance movies are so cheesy. The plot's thin and the acting's second rate. Why do people watch them?!" This is the polar opposite of meaty.


Meaty
Something is literally meaty when it is rich in high-protein meat. Figuratively, something is meaty when it is full of substance, that is, rich material that makes the mind think.
Ex.: "That documentary on the samurai was pretty meaty. There were lots of facts about ancient Japan in it." Thus, there was a great deal of detail and information.


➤  English Idioms in Formal and Informal Speech
In response to a question, I would like to take a moment and explain the relationship of this last batch of food idioms to English speech and discourse.

Idioms are, by their very nature, informal, for the simple reason that they cannot be read literally. You will never find idioms used in throne speeches by the Queen of England, or in government regulations.

You will find idioms everywhere else.

There are degrees of formality. Idioms may not be used to the same degree in high level business meetings as they are in workplace gossip about the local post office, but they will be used, because for English natives, they make comprehension easier, not harder. Often something can be expressed with an idiom far quicker and better than with a long sentence.

For the last three idioms we covered, the big cheese, a bad egg, and a bad apple, these expressions might seem slightly dated to the Facebook generation, but they are nonetheless very, very common in mainstream American English, the sort heard and spoken around the world. They are used in classic works of American literature. They are used without regard for the fact a non-native speaker might not understand them; all graduates of secondary education in America are expected to know such basic expressions. They are not slang; they are used across a wide range of speech, from the highly informal to the quite formal. They are just not used in perfectly formal contexts, such as those I mentioned earlier.

The reason I have not been assigning formality ratings or commonness of use ratings to my Idioms posts, with some sort of five-star system, is for two reasons.

One, I have made a point of posting only common English idioms, those commonly encountered precisely because they are used in a wide variety of circumstances. This may not have been obvious. Unfortunately, since that is the approach I have taken, it is a waste of everyone's time for me to explicitly say an idiom is common. Right now, they all are, because food idioms are so common in general.

Two, there is no systematic data on how common a particular idiom is. Furthermore, any such data would only be good within a particular region of the English-speaking world. An idiom commonly used in Alabama may be as rare as hen's teeth on Rhode Island. Even if I knew, frequency would vary by region and dialect to the point of being useless in a rating system.

So, I'm just doing the best I can with this. Thank you for your understanding, and do not be afraid of asking more questions. I appreciate them and am happy to reply.

➤ Read more idioms and phrases, English grammar and vocabulary at Basic English Grammar And Vocabulary .