What is hold your horses or have a cow?

"Hold your horses" is an idiomatic expression that means to be patient, wait a moment, or to calm down. The phrase likely comes from the world of horse racing and carriage driving, where holding the horses would mean preventing them from running or pulling the carriage until the time was right.

On the other hand, "have a cow" is another idiomatic expression that means to become extremely upset, angry, or frustrated. This phrase gained popularity in the 1950s and 1960s, likely from American slang. The origin of the phrase is not entirely clear, but it may have originated from a rural context, where cows were often considered valuable and losing one could cause a lot of distress.