What is be there or be square?

"Be there or be square" is a popular colloquial expression often used to encourage people to attend an event or gathering. The phrase implies that attending will be fun or important, and those who do not attend might be considered out of touch or miss out on something enjoyable or significant. The origin of "be there or be square" is based on wordplay: "square" is slang for someone who is conventional, old-fashioned, or not cool, so the implication is that if you don't show up, you're just not with it. This expression reflects a casual, playful approach to inviting someone to an event and is often used in social contexts among friends or peers.