The sink in Rebecca's kitchen is installed in a way it could not be used, facing into an island block with the taps at the edge.
Frasier tries to explain Lilith's joke about George Sand to the bowling team member who accidentally handed her a cigar, yet he is shown entering the bar too late to have heard the exchange and understood the context.
When Carla hangs onto a pair of corridor moldings while a powerful fan supposedly blows her completely horizontal, the cord supporting her is visible.