Atta boy Luther!

Is there where Adam Sandler got the gag that pops up in so many of his movies - "You can do it!" yelled by Rob Schneider or someone in the crowd.

During preproduction, Andy Griffith visited Knotts and went over the script. He pointed out that one line early in the film could be repeated several times and provide a recurring comic effect. The "atta boy, Luther" bit was Griffith's idea.

And the guy who says the line was actually one of the two scriptwriters! He'd written a lot of Mayberry scripts.

According to Svengoolie they use it in the movie Kingpin.