What is the conventional song that people in the UK and other nations often sing during New Year's celebrations?

"Auld Lang Syne" is practically synonymous with New Year's Eve celebrations, not just in the UK, but around the world! The song's origins trace back to Scotland, with Robert Burns, the famous Scottish poet, credited with writing down the version we know today in 1788. However, the tune itself is likely much older, a traditional folk melody. The phrase "Auld Lang Syne" roughly translates to "old long since" or "days gone by," and the song is all about remembering old friends and reflecting on the past year as you look forward to the new one. It's a moment of shared humanity, a nostalgic reflection on relationships and experiences. That's why it's the perfect song to sing as the clock strikes midnight on New Year's Eve. The other options, while potentially great songs or books, simply don't have that specific cultural connection to New Year celebrations.
Think of an old, traditional tune originating in Scotland that brings in the New Year cheer.