The tvtropes article itself notes that it isn't necessarily bad, which is interesting, and that it happened right after the very first season as well - such tha

The tvtropes article itself notes that it isn't necessarily bad, which is interesting, and that it happened right after the very first season as well - such that the 'golden era' had already had quite a bit of flanderization. At some point it ruins the characters, of course. All this makes me remember how different the very first season of the Simpsons was to the rest.