We've had missed opportunities in comics, and missed opportunities in Humorama so far... so then, how about some missed opportunities in TV and movies?
One that was mentioned in Chross's forum was in a show called Meet Mona McClusckey. The premise of the show was pretty dumb, even for a twelve-year-old boy, which I was at the time the show aired. An actress was married to a soldier and had agreed to live on only his earnings. (I can understand a man wanting his wife to quit her job to be a full-time mother, but to keep her job and not use any of the money she makes? Ridiculous!) But the star was Juliet Prowse, a pretty dancer with long shapely legs, so I watched and enjoyed.
There was an episode in which the wife had secretly spent some of her money to get an expensive household item and told her husband that she had found it on sale cheap. Near the end of the show, she confessed her misdeed and placed herself across her husand's lap for him to spank her. I was so excited seeing her in that position! The husband raised his hand... and... decided not to go through with the spanking! What a disappointment!
I bet Denny Miller, who played the husband was even more frustrated than those of us in the audience, to have Juliet Prowse's cute little derriere right there in front of him and not be allowed to give it even one swat!