you're gonna think i'm crazy...

I have this song stuck in my head and I know it's from Buffy. The problem is, I can't remember all of the words or else I would google it. It's something like this,

it's just a simple ________
i'm getting better all of the time

I have the tune stuck in my head and I'd really like to download it, so if anyone has any idea what I'm talking about or what episode it's from I'd really appreciate it!