When its not raining, everything. People smile at you. People look at you when you pass them in the street. "Is that traffic warden/cute lady/postman/cop coming on to me?" Nope its just sunny and people are happy. This took me a lot of time to get used to …
When its raining. Nothing (and it actually rains here quite a bit over the Winter months). Its just like in the UK when its raining (most of the time ;). This first hit me last week when I was walking through the City (as they call it over here). There I am on the sidewalk (pavement), rain hammering down, and everyone stampeding past, head down, glowering, hands in pockets. A UK-style cabbie drives past through a puddle, drenching some poor lady, and the illusion is complete. It was like I had been transported 5000 miles eastward.
So the next time someone comments that Californians are sooo friendly compared to the Mother Nation, just smile and ask them "have you been to Salford when its sunny?"