I've seen it a few dozens of times
The absolute last gag I caught (there are sooo many) was when Rex Kramer was leaving his house. He comes down the stairs, wife hands him his hat, they flash to the private getting mauled by the dog, then come back to a shot of only Rex's reflection in the mirror while he adjusts his hat.
The then says "let's go" and >steps out of the mirror<. I never caught him coming out of the mirror...at least 2 dozen viewings and I consistently missed it. I was genuinely excited by finding "the last gag".
If you push something hard enough, it will fall over. Fudd's First Law of Opposition
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