At the end of every episode, Eric's stress becomes so bad that the vein on his head strangles him.
For the US broadcast of the first season, Eric was changed to an American and Hank Azaria re-dubbed his voice.
In every episode, Mrs Wilson is trying to get a letter in the mail and it always ends up going in the sewer.
The sounds heard before Eric's stress vein strangles him are a cat angrily meowing, gunfire, glass breaking, and a submarine's dive alarm.