The later seasons of World's Dumbest feature a segment called "What We've Learned So Far," in which a cast member summarizes several of the clips that have already been shown. During one episode, an Australian man jams a knife into a toaster, which violently explodes. (The openly gay) Brad Loekle sums the clip up with "Don't stick things where they don't belong!" while showing the exploding toaster, followed by a CGI rendering of Loekle himself exploding.
During a clip in which a model fell through a hole in the runway, Kevin sarcastically commented that "She couldn't be bothered to look where she was walking; she was too busy modeling." Models actually are taught to never look down, or really in any direction other than straight ahead, so if she had seen the hole, she would have technically been using incorrect form.
At least two clips feature someone who is blindfolded and then pranked by his friends into thinking he's bungee jumping (which would be a very long fall) when it turns out he's merely falling a very short distance (at most, roughly three or four feet). Wouldn't a better prank be making someone think he's only going to fall a couple of feet and having them fall a very long distance? With the former prank, the "prankee" is already prepared and energized with adrenaline for a long drop, so what exactly does the unexpectedly short fall cause besides disappointment?
Well, he's not properly braced for a short drop, so there is the "WTF just happened?" factor.
In a 911 animated reenactment, an elderly man calls for an ambulance for the persistent chest pain he was having for over an hour, but the ambulance driver couldn't figure out where he lived, so after a while of getting lost, the man calls 911 again and tells them to cancel the ambulance, that he was having his wife drive him to the hospital, "I don't have time for you to try and figure out where we are." Which begs the question, why didn't his wife just take him to the hospital herself in the first place?
In a "Brawlers" clip of a few teens taping a pair of ducks attacking each other, they remark hoping they might drown each other, to which Brad comments, "They can't drown, douche bags, they're ducks." But ducks actually can drown one another, if one overpowers another and manages to obstruct its breathing while keeping its head underwater long enough.
One husky-built dumb criminal tries to break into a fast food restaurant by trying to climb through the drive-thru window - which he can't fit through. At one point, he walks away, returns wearing a thick sweatshirt, and tries again. Even Nick DiPaolo remarks, "Now he's got a sweatshirt on. Yeah, now he'll fit!"