Continuity mistake: When SpongeBob tries to steal the gum at night, he's dressed as a bandit, but then the next day when Sandy finds him, he's wearing his normal clothing. He was stuck in the gum all night so there's no way he would have changed.
Continuity mistake: When the fish is at the front desk of the Krusty Towers, there is a silver bell on the desk. When Patrick arrives, there is no bell. Then Mr. Krabs puts Squidward in his place, and the bell is back, but has moved to the opposite side of the desk.
Continuity mistake: When we first see a far shot of Squidward's house, there is no potted plant on his porch. When Squidward steps out, the potted plant appears, and he rights the crooked flower. The potted plant disappears in the rest of the shots of Squidward's house.
Continuity mistake: In "Chocolate With Nuts", Patrick and Spongebob buy the chocolate holding bags from one man, they walk to the next house next door. When they are standing next to the door, the first house behind them disappears.
Continuity mistake: In "My Pretty Seahorse", Spongebob is walking outside with Mystery and a customer with a drink and a plate is watching him go by. In the next shot, Squidward places a bowl of onions underneath his face, and his plate and drink have disappeared.