The great thing about minecraft is being able to choose which version to play on. maybe you like 1.20 where they added Camels and bamboo wood, or maybe you prefer 1.19 where servers had more independence. Or maybe you are old school and prefer your poppies being called roses and your spiders not being able to jump two blocks high.
i like 1.12.2 because of its mod support, but my favorite for playing vanilla is beta 1.7.3; i prefer its gameplay and worldgen over the newer versions