The original ending had Carol and Jerry getting drunk on VIP and checking into a hotel. Doris Day insisted the concluding events be rewritten, having Carol and Jerry get married in their drunken state before going to bed.
At one point in the film, Jerry and Carol talk with an aquarium behind them, which holds a fish that is eaten by another as the scene ends. The "aquarium" is clearly just a short loop of film being played forwards and backwards in succession - the fish repeats the same two motions over and over until it is eaten.
When Carol takes Jerry to the beach, at the end of the scene, Jerry has the blue towel in his hand as he lies back into his seat, as Carol lies back next to him into her seat, the blue towel is now draped over the back of both their seats.