Revealing mistake: After the crowd boos at Homer after kicking the bomb, Bart is shown walking past The Android's Dungeon and the shot pans over to show Comic Book Guy. Just as the shot begins to pan over, it can be seen that Comic Book Guy randomly pops up on screen.
Revealing mistake: After Homer knocks out the guard guarding the dome, Homer runs into the supplies shack. As he walks through the doorway, his right arm passes through it.
Revealing mistake: When Moe is emptying the beer bottles into the lake, his face is seen turning around without any animation. (00:19:20)
Revealing mistake: When Grandpa is being rolled out of the church, everyone is looking at him. As this happens, look closely at the Squeaky Voiced Teen sitting next to Hans Moleman on the right hand side of the church. As he turns his head around you'll see his eyes disappear as he stops turning his head. (00:06:05)
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