Humans express gratitude in a number of ways. For example:
"Thank you" is a common way to show gratitude. It is only a word and is not worth the same as what youve been given.
"Returning" a favour is another way to show gratitude. It is commonly used when they have gotten you out of trouble.
"Owing" someone a favour is used when someone is in a rush. It does not make sense since its not a material thing
Humans give away their resources in exchange for two words.
