Of all the daughters, they thought that Vanessa would be the one to really walk the straight and narrow. She'd already proven them wrong with the "Alphabet game" and the "Off to See the Wretched" episodes. However, no one thought she'd get engaged and say nothing for 6 months!
The look of total shock on Cliff and Clair's faces was priceless, almost as shocking as Denise's marriage announcement. Cliff's analogy of the engagement announcement to presenting a well cooked & expensive steak dinner served on a garbage can lid was the absolute best.
This episode was one of the show's all time best.