"Probably not, but it would have been the polite thing to do."
"The polite thing is to drink out of a glass."
It was the polite thing to say under the circumstances.
The polite thing to do in these circumstances would be to close the door again, get on his bike, and ride away.
So the polite thing to do is to behave as if the bubble were still there.
I told myself that was the polite thing to do.
I figured the polite thing was to just ignore them.
He stood now, to do the polite thing as host.
The other will say polite things about the winners and go home disappointed.
"I thought it might be the polite thing to do."