The man wrote SO many truisms that people really identify with, it's hard to keep track. A couple of my favorites:
"My uncle ordered popovers
from the restaurant's bill of fare.
And, when they were served,
he regarded them with a penetrating stare.
Then he spoke great words of wisdom
as he sat there on that chair:
"To eat these things," said my uncle,
"You must exercise great care.
You may swallow down what's solid,
but you must spit out the air!"
And as you partake of the world's bill of fare,
that's darned good advice to follow.
Do a lot of spitting out the hot air.
And be careful what you swallow."
"Those who mind don't matter and
Those who matter don't mind"
Damned wise words, Theodor!