A snake wriggled across the warm highway. Al zipped over and ran it down and came back to his own lane. "Gopher snake," said Tom. "You oughtn’t to done that."
– John Steinbeck
The Grapes of Wrath, Chapter 26. Tom Joad’s reprimand of Al for killing a snake shows how he has grown and matured since his own rattlesnake killing act in Chapter 18.