Bee Gees, ABBA and ELO do not deserve to be on this list. These bands were staffed by some of the finest pop tunesmiths of the latter half of the 20th century.
Back on topic (after stepping off the soapbox): here's a bad song everyone can agree on and still love
(wait for it)
"Da Da Da" by Trio.
Admit it; it's stupid, but it sticks in your head. And how about "Mr. Roboto" by Styx?