Oftentimes major keys are called "happy" and minor keys are "sad". Why is this? Is it universal across cultures that use these scales? Do similar connotations exist in other scale systems?

Edit: If this isn't universal, then could someone perhaps provide an explanation of why it is that in some cultures, minor keys are supposedly sad?

Oftentimes major keys are called "happy" and minor keys are "sad". Why is this? Is it universal across cultures that use these scales? Do similar connotations exist in other scale systems?

(If this isn't universal, then perhaps someone could explain which cultures it is sad in and why.)

Oftentimes major keys are called “happy” and minor keys are “sad”. Why is this? Is it universal across cultures that use these scales? What about in other scale systems – do similar connotations exist?

Edit: If this isn't universal, then could someone perhaps provide an explanation of why it is that in some cultures, minor keys are supposedly sad?

Oftentimes major keys are called "happy" and minor keys are "sad". Why is this? Is it universal across cultures that use these scales? Do similar connotations exist in other scale systems?

Edit: If this isn't universal, then could someone perhaps provide an explanation of why it is that in some cultures, minor keys are supposedly sad?