I think every primary has a theme song, and as soon as I explain you will know exactly which one is yours.
When I was in our previous ward (before the split) the kids requested "Once there was a Snowman" every Sunday. Sometimes two or three times a Sunday. It was their theme song. I got really tired of singing that song every single week. Anytime the kids could request songs, it was always that song!
When the ward split I tried not to sing that song very often. Today I offered to sing it with the kids and they commented that we never sing anymore. So I told them that was the theme song of the other ward. Then I said I didn't know what our ward's theme song was and a bunch of kids at the same time said "Hie to Kolob". That's true. That's our song. It's requested every week. Sometimes multiple times, even though we have already sung it.
I imagine every primary has a song like that. What's yours?