where's the beef?

1. Also, what's the beef ? What is the source of a complaint, as in Where's the beef? No one was hurt in the accident . This usage employs beef in the sense of a “complaint” or “grudge,” also appearing in the phrase have no beef with , meaning “have no quarrel with.” [ Slang ; late 1800s]

2. Where is the content or substance, as in That was a very articulate speech, but where's the beef? This usage was originally the slogan for a television commercial for a hamburger chain attacking the poor quality of rival chains. (1984) The phrase was almost immediately transferred to other kinds of substance, especially in politics.