Courtesy costs nothing proverb
Being polite or behaving in respectful manners is easy.
You should have said "hi" to everyone when you came because courtesy costs nothing.
I know you don't like him, but courtesy costs nothing.
Although there is scant information about its initial use in literature, it is thought that this proverb was first used in the 18th century. A proverb from the 15th century French has a similar meaning: Courteous words cost little and are worth much.
If you do something or something happens in a blaze of glory, you do it or it happens in an extraordinary and impressive manner.
The band intended to perform publicly and go out in a blaze of glory.