My personal experience is that "earworms" are caused by not hearing the ending of a song. For me its usually the song that is playing when I walk out of a store

My personal experience is that "earworms" are caused by not hearing the ending of a song. For me its usually the song that is playing when I walk out of a store, or the song thats playing on the radio when I turn it off. If I know the song well enough and I am able, playing it out to the end in my head gets rid of it.