Stick in my head

Why is it that when I get a song stuck in my head, it's typically a song that's annoying or that I'd rather forget? But when a song comes along that I enjoy and it actually uplifting, I have to try and work to keep remembering the words?
That's how it was today with a wonderful song by Al Green:

Everything is going to be all right...
He's coming back for the true and good,
like he said he would.

At least I think that's an Al Green song. I can't find the lyrics online and maybe my mind is just playing tricks on me. Amazing that this was a four day week but I feel so exhausted. It must be all the stress and all my co-workers who are giving up on journalism. That definitely gets depressing.