Blackjack rules can vary significantly across different countries, influencing aspects such as the number of decks used, dealer actions on soft 17, doubling down options, and whether surrender is allowed. Some regions might incorporate unique local variations or side bets to add complexity to the game. These differences can affect players' strategies, as local rules might change the house edge and overall gameplay experience. Cultural influences also play a role, with certain betting habits or etiquette shaping how the game is played in specific areas.