If you examine 800,000 hotel reviews from genuine guests you would presumably get an interesting snapshot of what makes a guest swing from hating to loving a property.
This is what Priceline-owned Booking.com has spent a fair amount of time doing recently as part of a project to find out more about what keep its users happy (or not).
The study of reviews was combined with a survey of 1,200 customers in the US.
[Click on the image or here for a larger version]
NB: Full study here on The Booking Truth.