According to Zac_Pundi, Bitcoin Pizza Day marks the anniversary of the most expensive meal ever, when 10,000 BTC were spent on two pizzas in 2010. This milestone is a recurring reminder for crypto traders of Bitcoin's volatile price history and long-term value appreciation, which often drives increased trading volume and speculative activity around May 22 each year (source: Zac_Pundi on Twitter, May 22, 2025). Traders use this date to reflect on market cycles, historical highs, and to anticipate potential volatility in the Bitcoin market.