Help!

Can someone please tell me why songs get stuck in my head?

Today's greatest hit is from the family classic, 'The Sound of Music' whereby the beautiful, and perhaps the slightly androgynous, Julie Andrews, sings with the most dreamiest man in his time, Christopher Plummer, "Something good".

Also, I would like explained how I know all the words to the above mentioned song, when I have seen it on a yearly basis for about 10 years?

Don't get me wrong, I love the song, but not stuck playing like a broken record in my brain. Here's the lyrics, so you can share my pain. (Try to imagine staring into Christopher Plummer's bedroom eyes....ahhh....)

(Maria) Perhaps I had a wicked childhood, perhaps I had a miserable youth
But somewhere in my wicked, miserable past, there must have been a moment of truth
For here you are standing there loving me, whether or not you should
So somewhere in my youth or childhood, I must have done something good
Nothing comes from nothing, nothing ever could
So somewhere in my youth or childhood, I must have done something good.
(Captain) For here you are standing there loving me, whether or not you should
(Maria) So somewhere in my youth or childhood, I must have done something good.
(Both) Nothing comes from nothing, nothing ever could
(Maria) So somewhere in my youth
(Captain) or childhood,
(Maria) I must have done something,
(Both) something good.

Oh you did something good alright there Captain! Indeed! Sing is like you mean it! (I notice that this post took a different turn than I intended... Liz is dreamily imagining C.P in the gazebo....)