What is the most popular greeting?

Good day! Could you please enlighten me on the topic of greetings? I'm particularly intrigued to know which greeting is the most popular among people worldwide. Is it a traditional handshake, a warm hug, or perhaps a polite bow? Does the popularity of a greeting vary by culture or region? And furthermore, have there been any notable changes in the most popular greeting over the years? I'm eager to gain a deeper understanding of this fascinating aspect of human interaction.