Why do we say "Keep your feet on the ground"?

Meaning:

A person described as having their feet on the ground would normally be someone who is seen as realistic and practical, and most likely down to earth and genuine. Although usually used positively, it is possible for the expression to be used in a negative form if the person is characterized as being boring and not a risk taker.

Background:

It is first attested to in the USA in 1931. An early variation can be found in John Steinbeck's The Grapes of Wrath (1939):

Tom grinned. "Keep all four feet on the groun'," he said. "I didn' mean nothing'. Jus' take her easy over this ditch."

More expressions and their source

Challenge yourself with BookBrowse Wordplays