Here's a question a friend asked me over dinner: do people in different parts of the city have different moods — and does it show up in their Google reviews? Her thinking went like this. A McDonald's is a McDonald's. The Big Mac in Woodlands is the same Big Mac as the one in Bedok. So if one neighbourhood gives its McDonald's four stars and another gives it three, that gap can't really be about the food. Maybe it's about the people doing the rating. Maybe some neighbourhoods are just…...