The phrase "Break a leg" is commonly used to wish someone good luck, especially before a performance or presentation. Despite its literal meaning being quite negative, it has become a theatrical tradition and superstition.
Here's an explanation of the phrase along with examples: In the world of theater, saying "good luck" is considered bad luck. Therefore, actors and performers started using the phrase "Break a leg" as a way to counteract the jinx. The phrase implies wishing someone so much success that they would need to take a bow (i.e., break a leg) after a remarkable performance.

Example: Before a theater production, a fellow actor might say to their colleague, "Break a leg tonight! You've worked hard, and I know you'll give an outstanding performance."
Example: A group of friends might use the phrase jokingly to wish their friend good luck before a public speaking competition. One of them might say, "Hey, go out there and break a leg! You've got this!"

While it may seem counterintuitive, "Break a leg" has become a playful and encouraging way to wish performers success and acknowledge their talent.