What's wrong with me???

So I'm walking down the basement steps when, out of nowhere, the following pops in my head...

"Drink Dr. Pepper, the joy of every boy and girl!
It's the most original soft drink every in the whole wide world!
Dr. Pepper!"

Which prompts the following questions:

Why is this still in my head? Whatever happened to David Naughton? Seriously, what is up with my brain?