Ifs and Buts is a term used to describe the reasons people give for not wanting to do something. To show that you don't wish to accept any excuses, you can tell somebody that you wish to hear no ifs or buts Here IF & BUT have become nouns
This indicates that the person described is unaware of his or her good fortune or is unaware of how difficult day to day life was before he/she was born. Typical usage: 'Kids today don't know they are born'.
To end on a muted note - most likely in a situation where one would have expected a more spectacular finish. This expression was coined by T.S. Elliot in his 1925 poem, The Hollow Men, which ends: This is the way the world ends This is the way the world ends This is the way the world ends Not with a bang but a whimper.