According to Hosfstader, Lakoff and others, metaphor is the core of cognition, the basic algorithm upon which all else runs. It is deeply embedded in the way we perceive the world, and this is reflected in our language; Lakoff catalogued some of the "metaphors we live by" in his book of the same name, and it is surprising how transparently we use metaphor all the time without even being aware of it.
As an intuition pump, consider the following vaguely associated words and their antonyms:
up / good / positive / forwards / fast / white / on / daytime / hot / red / aroused / friendly
down / bad / negative / backwards / slow / black / off / nighttime / cold / blue / bored / indifferent
I'm sure you can add more. You can pick almost any pair of these words and find a phrase that relates them - "I'm feeling blue because Claire called off our date; she's been cold ever since Dave bad-mouthed her."
Interesting, that book caused me to question what I really know and hold my views on metaphore. When you see slime mold "learning" and decent AI emerging, it really starts to throw a wet towel on how amazing we think humans are in general because of our intelligence. Then there's election night.
As an intuition pump, consider the following vaguely associated words and their antonyms:
up / good / positive / forwards / fast / white / on / daytime / hot / red / aroused / friendly
down / bad / negative / backwards / slow / black / off / nighttime / cold / blue / bored / indifferent
I'm sure you can add more. You can pick almost any pair of these words and find a phrase that relates them - "I'm feeling blue because Claire called off our date; she's been cold ever since Dave bad-mouthed her."