Supposedly at a dinner party celebrating the completion of the film, either Maureen Stapleton or Paul Lynde (the story would make sense featuring either of them) stood up and said, "Ann-Margret, I want you to know that I'm the only person who worked on this film who doesn't want to [have carnal relations with] you.
Director George Sidney was so taken with the talent of Ann-Margret that when the film was edited he went to Columbia's executives and proposed the opening and closing bumpers that would showcase her. They refused to pay for any additional filming so Sidney rented the studio and crew at his own expense. He then asked the composers to come up with a title song. Ann-Margret's skirt-flipping/hair-tossing rendition of the song was filmed six months after principal photography was completed at a cost of $60,000, which was repaid to Sidney after the movie, and Ann-Margret, became a sensation.
After singing the final line of "One Boy," Rosie sits down on the balcony steps and wraps her arms around a support post. As the camera pulls away near a tree branch, the film cuts to a different take and Rosie's hands aren't in the same position as they were a split second before.
The turtle that zooms off a table and out a door is clearly a prop mounted on top of a dolly several inches thick that holds the turtle above the table and floor. The prop must have wheels as it slides so smoothly across the floor.
After Albert gives the pet turtle the initial version of the "Speed-Up" drug and the turtle speeds across the floor, then up the steps to the front door, reflections of the teens entering the door can be seen in the glass plate that they used to allow the turtle to get up the stairs.