“You with the purple shirt,” said Ellen DeGeneres, pointing at Jim Madaffer in her studio audience on Tuesday’s show. “We’re going to give you some music.” His assignment, as one of only a handful of “dads” in the talk host’s audience that day, was to do the “Dad Dab” dance. Thus, the chairman of the San Diego County Water Authority Board and California Transportation Commission member squeezed out to the center aisle and gamely gyrated to the music, earning a thumb’s down from the show host.