I've now caught myself on more than one occasion doing something I never would have even bothered doing before I had a child. I've caught myself singing songs like "She'll Be Comin' Round the Mountain", "Sesame Street" theme song, and some other unknown song that the Peek-a-Boo Elmo toy makes when Kali 0.2 plays with it. It's one of the few things that keeps her busy and entertained, so I have no choice but to listen to it or be faced with a fussy and bored baby.
So if you're hanging around me and I start to sing nursery rhymes, just ignore me. I've got the parent disease.