Continuity mistake: When Homer brings his pet pig home to meet Marge, they enter the kitchen and the roll of paper towels is hanging under the cabinet near the window, but in the closeup when he and the pig share a carrot the paper towel roll and its holder have both vanished, and then they reappear. A cutting board suddenly appears on the counter as well. (00:15:30)
Continuity mistake: When Homer is grooming Spider Pig he is in Bart's room and it's on the end of the house because you can see the corner of the house, then he walks out of the room and goes in another room but that room is on the end of the house too, you can tell it's a different room by looking in the background so it doesn't make sense that both rooms are in the same place. (00:15:45)
Continuity mistake: During Bart's flashback of him and Homer fishing, Homer drops the bug zapper into the lake. Dozens of fish come floating to the surface all over the lake. After the shot where Homer scoops up a fish and is zapped for it, there's a reverse-angle shot of Bart with no dead fish in the lake around him. (00:16:30)
Continuity mistake: When Homer drops the bug zapper in the pond, we see he still has the wire in his hand. Camera cuts to him about to grab a fish and the wire has gone. (00:16:45)
Continuity mistake: When Ned offers Bart some cocoa, we can see the cocoa is the only thing in his hand. Then in the next shot, some whipped cream has appeared in his hand out of nowhere. (00:17:25)
Continuity mistake: After Marge says "How did the pig tracks get on the ceiling?", she turns her head to the left and opens her mouth, but in the shot that follows, her mouth is suddenly closed. (00:17:50)
Continuity mistake: At the start of the scene where Lisa is describing Colin to Marge, there is water on the floor Marge uses to clean the pig tracks on the floor with. In the next shot, there is suddenly a lot more water on the floor than there was in the previous shot. (00:17:50)
Continuity mistake: During the town hall meeting, on the lower floor there are two sections of seating divided by an aisle, and in every shot of the audience we see people switch seats or sections they're in, and some clothing changes as well. Just a few examples: 1) the Sea Captain's first seated behind Moe and Lenny, then he's behind Willie; 2) Krusty, Mel, and Luigi are behind Bumblebee, but the next closeup has Mel seated in front of Luigi and Bumblebee, and Krusty has vanished, but he reappears when they spit the water; 3) And in that same shot the guy behind Luigi is wearing a white jacket and purple shirt, but when they all gasp he's wearing a black shirt and green jacket. And so on. (00:19:20)
Continuity mistake: During the town hall meeting, Mayor Quimby's podium has a recessed panel at the front which vanishes when he asks who's in favor of a new scissor lift platform. (00:19:50)
Continuity mistake: At the town hall meeting, when Lenny says, "It's not so bad," there's a single head light fixture on the wall near the balcony, but when Moe shouts, "This is why we should hate kids," there's a double head fixture on the wall, and yet in the first overhead shot of the meeting there's no fixture at all in that space. (00:20:05)
Continuity mistake: When the wall is put up around the lake it is built right next to it, but when Homer dumps the silo the wall's much further away from the water. (00:21:15 - 00:24:05)
Continuity mistake: In the scene where Mayor Quimby says "To make sure this wall is completely idiot-proof...Cletus", in a far shot, Cletus comes walking up with his hands empty. It then cuts to a close up and now you can see the opossum tail in Cletus' right hand. There is no time for him to have grabbed it from anywhere. (00:21:15)
Continuity mistake: When Marge asks Homer about Spider-Pig "What are you doing with his leavings?" Spider-Pig is looking straight forward at the TV. In the next shot, Spider-Pig is suddenly looking at Homer. (00:21:30)
Continuity mistake: When we see the news report of the silo being lifted out of the lake, the height of the silo has significantly decreased, compared to when it was in the Simpsons' backyard - note the empty space below the drawing of the pig. (00:21:30 - 00:30:50)
Continuity mistake: When Lenny calls Homer about free doughnuts Hans Moleman is in the background (in Lenny's scene) then Homer drives to the lake to dump the pig crap silo and he runs over Hans Moleman, but he was at the doughnut shop so he couldn't have gotten to the lake in time. (00:22:30)
Continuity mistake: When Marge and Homer are in the backyard with the silo, there is a drawing of a pig on it, but in Homer's close-up with part of the silo in the background, the part of the silo that's visible should have the pig drawing at the top, but it does not. Later, when the silo's found in the lake, the words and drawing differ and are much lower on the silo. (00:22:30)
Continuity mistake: When Homer drives to the lake to dump the pig crap silo, there are hundreds of 'No Dumping' signs along the way, but on the way back, all the signs are gone, including the ones Homer missed. (00:22:55 - 00:23:40)
Continuity mistake: When Homer dumps the silo in the lake, there are the words "Pig Crap" on the front and there is no writing on the back. However, when Lou and Eddie find the silo later in the movie, the "Pig Crap" words are there, but the words saying "Return To Homer Simpson, No Reward" has appeared out of nowhere. (00:23:00 - 00:30:50)
Continuity mistake: When Homer cuts the ropes securing the Pig Crap Silo to the car, he leaves an axe mark on his car. In the next shot the mark is gone. (00:23:05)
Continuity mistake: When the silo has been dumped and the pollutant begins spreading, there is no rope on the ground behind the car, but when Homer gets back into the car to drive away, there is a bunch of rope lying on the ground behind the car. (00:23:05)
Answer: Homer has been known not to make the smartest decisions, and the decisions he does make, he makes without fully thinking them through. Clearly he wanted to get some donuts as quickly as possible without thinking of any other ways, so he decided to ditch the silo in the lake as it would be the fastest way of getting it off his back, even if it's not the smartest. Also, putting that aside, he likely wanted his own pick of the donuts rather than have Lenny guess what he wanted.
Casual Person