There is a controversy raging via e-mail about the major/minor : happy/sad connection: whether it applies to all music, what notable exceptions people can name, and so on. (These are music theorists carrying on, in case you wonder who would care enough about this to engage in ongoing debate.)

I found it reassuring when someone voiced impatience, saying that surely the topic merited more refined treatment than eithers and ors. I think immediately of Mozart's Piano Sonata in G which trembles between major and minor from its very first two pickup notes. When Mozart writes in a major key it is never just in major, though sometimes the deviations are only barely discernible. Such elements enliven his line. No theory can adequately explain or even find them. In fact, theory often gets in the way by accounting for wholes when it is details that hold us enthralled.