 In the episode , David Letterman portrayed a self @-@ help group leader by the name of " Ellsworth " offering ERK or Ellsworth Revitalization Konditioning . Mork ( Robin Williams ) and Mindy ( Pam <unk> ) attend one of Ellsworth 's trainings at the suggestion of their friend Susan ( Morgan Fairchild ) , where they endure Ellsworth 's authoritarian brand of group therapy . Mork points out hypocrisy in Ellsworth 's teachings , and exposes him as a fraud . The episode has been called a parody of the Erhard Seminars Training or " est " course . The episode received mostly positive reviews , and was highlighted as one of the season 's best episodes , along with " Mork 's First Christmas " and " Mork 's Mixed Emotions " . David Letterman 's performance as " Ellsworth " also received good reviews . 
