"I was at a Grammys party … and I went to the ladies room and on my way in I saw this little old lady sitting at the end of the bar. And she was asleep," Summer told "Nightline." "She was the bathroom attendant. And at that same moment, a group of ladies walked into the room and started spraying their hair and doing all these things. And my first thought was 'God, she works hard for her money, that lady.'
"And then I thought, 'Man, that's a song,'" she said. "So I went and grabbed my manager, and we went back into the bathroom and started writing the song on a piece of toilet paper."
Summer won five Grammy awards, and became the first artist to have three consecutive double albums reach No. 1 on the U.S. Billboard chart. She continued to record into the '80s, '90s and 2000s, releasing her last album, "Crayons," in 2008.
At the height of her fame in 1979, Summer declared herself a born-again Christian and relied heavily on her faith. "God, spirituality and religion -- she was very sincere about that part of her life," her former publicist Michael Levine told ABCNews.com. "She had a weekly Bible study at her house."
Levine added that Summer exuded "great optimism" and was "exceedingly polite, seldom visiting without bringing a gift."
"She was someone who felt love and made other people feel it," Levy said.
Summer is survived by her husband, Bruce Sudano, their daughters Brooklyn and Amanda, as well as her daughter Mimi from her previous marriage to Helmuth Sommer.