"Happy Holidays", specifically the Andy Williams version. Because in my office at this time of year, they put the Christmas music station on. Every time my manager hears this song comes on, she winds up singing the line "Hoop de do, and dickory dock", just that line, for the rest of the day. Every time she walks by. In a very exaggerated voice. Of course, the song comes on multiple times a day, so she's bound to catch it at some point. I dunno what her fascination with it is, but we're all freaking traumatized after multiple years of this.