The fixation around couples shared/non-shared finances.
Soap vs shower gel debate (seemingly ongoing).
Again, seemingly ongoing discussions about how much people earn, what they do with it, how much/little money that is, compared to whatever else.
The offer of legal advice from someone who clearly has no clue about it.
'Which backpack / handbag should I buy with my 50p / 10 grand budget' - I dunno, try looking at the other threads that come up every week.
Good / crusty bread 
The regular amazement at regional differences in accents / words used / house prices, weather, and so on.