Always knock before entering. Don't let the ants get in the sugar.
5 seconds sound clip from the Happy New Year, Charlie Brown! movie soundboard.
You can hear this line at 00:19:08.881 in the VHS version of the movie.
Quote context
[...]
- I bet you'd like that, eh, Chuck?
- It's been a great year, Chuck. You'll have to admit that.
- What do you think, Chuck, would be good rules for living in the new year?
- Keep the ball low. Don't leave your crayons in the sun.
- Use dental floss every day. Don't spill the shoe polish.
- Always knock before entering. Don't let the ants get in the sugar.
- Never volunteer to be a program chairman.
- Always get your first serve in. And feed your dog whenever he's hungry.
- Will those rules give me a better life, Chuck?
- A better life and a fat dog.
- Have you made any New Year's resolutions, Chuck?
[...]