This may follow in the same vein as what people say verses what they write, but it is a bit different than what's been addressed prior I think...
"Imagínense" is addressing several people while "tu novio te lleva" is addressing one person (informally). I would have expected either "Imagínense...su novio..." or "Imagínate... tu novio...".
"Imagínense que sin motivo tu novio te lleva, nervioso, a cenar a un restaurante."

Steven-W15
September 12, 2014