After Bender drinks a glass of oil from the stand he puts the empty glass back but immediately after all the glasses are full again.
At Elzar's restaurant there were 7 people eating, yet Elzar brought only 5 chocolates for their dessert.
When the Robot Mafia are on the Planet Express Ship they find that a robot is listed on the crew; meanwhile, Bender is trying not to let the mafia know that he is the robot on that list. Problem 1: the crew roster would have shown his name. Problem 2: the Crippled Kid robot delivers Bender's cut to Planet Express' office. Either way, the mafia would have known that he was part of the crew.