Copy Cat
In season 4 during the scene where Janet is explaining Jack’s absence to the cop, she says, “It could be days, weeks before he comes back”. Well, she also said the exact same line to the FBI agents in Jack on the Lam.
Bumpy
Things got a bit bumpy in Season 7 Episode 1 titled rightly so, A Night Not to Remember. You can clearly see John Ritter bans his head on the table as he is sliding down underneath it at the end of the restaurant scene. Later he mentioned that it actually knocked him unconscious and he performed the rest of the show with a visible welt on his temple. Ouch.