to say the least
to put it mildly
To understate; express as mildly as possible.
After all we did for him, his behavior toward us, to say the least, was a poor way to show his appreciation.
you don't say
Used to show surprise at what is said.
Your ring is a real diamond? You don't say!
"Bill and Jean are going to get married." "You don't say!"
you said it
you can say that again
Used to show strong agreement with what another person has said.
"That sure was a good show." "You said it!"
"It sure is hot!" "You can say that again!"