Why did I have this false belief about the song Supercalifragilisticexpialidocious?

[salemfan]

Until I watched one of the Disney Sing-Along Songs videos in my elementary school music class, I incorrectly assumed the song "Supercalifragilisticexpialidocious" was from Diagnosis Murder, but after I watched a Disney Sing-Along Songs video in my elementary school music class, I realized the song "Supercalifragilisticexpialidocious" is from Mary Poppins. Why do you suppose I incorrectly assumed the song "Supercalifragilisticexpialidocious" was from Diagnosis Murder?

 

[CensoredAlso]

Well Diagnosis Murder did star Dick Van Dyke, who also starred in Mary Poppins.

 

[Muppet fan 123]

I don't knoe how you got from Mary Poppins to Diagnosis Murder

 

[CensoredAlso]

I don't knoe how you got from Mary Poppins to Diagnosis Murder

Like I said above, there is a common thread.