In HHGTG, Arthur needs a Bablefish to understand the Vogon - just after said Vogon communicates to 'people of Earth' in perfect English (which every nation understands, even the Americans)... In that awful fourth boook, the demolition never even happened, which makes a mockery of everything so far, especially the narrator's repeated references to 'the only two survivors'. Bollox.
In The Young Ones' Cash, Vyvyan's baby is a false alarm, but real enough to kick Wrik and send him into the fireplace.
In Happy Families, the second sister is baptised Madelaine, but her liaison only starts when she's older - coincidence? Also, I've never got the relationship between Edith and Guy. Despite the age difference, the action implies she's the mother - she's certainly like my mother, and I say that with all due respect to Edith. This implies Grandma is an unaffectionate nickname, but on several occasions she talks to him about her ex-hubby as 'YOUR grandfather.' If there is a generation inbetween, why are they never mentioned, and why did they let her kick their daughters out? I guess we'll never know.
In Tom and Jerry, the poor feline is burnt to a crisp but returns a picture of health in the next scene. This is impossible unless he had plaastic surgery, but how would a domestic beast raise such money? He could use the NHS, but the waiting lists are massive and this would contradict the strict chronology of the episode. They must have made this part up and used stunning special effects or a stuntcat.