Mr. Burns mocks Homer's weight

During "Brush with Greatness", Homer is attempting to lose weight after being humiliated on the news when he got stuck at Mount Splashmore's H2WHOA! slide. After losing 21 pounds, which brings his weight down to 239 pounds, his wife Marge congratulates him for his achievement, only for Mr. Burns to cruelly mock his weight-loss efforts by calling him "the fattest thing he's ever seen", which completely shatters his self-confidence in one fell swoop and causes Homer to start binging on food again. Meanwhile, a furious Marge kicks Mr. Burns out for his mockery of her husband's attempt at losing weight and says that she can finish the portrait by herself and have it finished in time for the unveiling.

Example of:
Kick the Dog