At the steak house, the steak on Brain's plate disappears and reappears throughout the scene.
Lois tells her father that she is in her forties, therefore she would remember her brother who had only been locked up in the asylum for 30 years, rather than him remembering her.
Patrick is standing in the kitchen when Peter announces his plans to start the National Association for the Advancement of Fat People; yet in a later scene he asks Peter about it as though he didn't know about Peter's coalition.