It is polite to offer friends a place to stay.
Ross' house is messy, but he has some friends flying in from out of town to visit him.
Ross wants to avoid being inconvenienced by his friends.
Ross hires a cleaning service to come clean up the mess in his house before his friends visit.
Ross tells his friends that his house has water damage, and they need to stay somewhere else, even though it's not true.
Ross' friends appreciate being given a clean place to stay and make an effort to stay more in touch after the trip.
Ross' friends find out that his house did not have water damage and it made the rest of the trip awkward.