You don't know what you're missing, son.
4 seconds sound clip from the Blackbeard's Ghost (1968) movie soundboard.
You can hear this line at 00:25:24 in the Blu-ray version of the movie.
Quote context
[...]
- Now, to real business. Where'd you stow it?
- What?
- Ship's stores. Have to seek succor there. Tsk, tsk, tsk.
- Mistress Stowecroft, your humble servant. Servant...
- A bottle of rum, no glasses are left to drink from the bottle with you, sir. Me dee, fiddle de dee.
- You don't know what you're missing, son.
- She didn't see you. She didn't even hear you.
- You mean... No one can see you except me?
- Are you sure you don't want to freshen your spleen?
[...]