I liked how TNG kept the Trill sacred by making them completely different. Oh and they did that with the Ferengi too, they were super sacred in those days. And then there was that great sacred Klingon moment when Worf was dressed like a cowboy on that old west train, that was almost holy that scene.
But all that aside you know what they took really seriously? Romulan shoulder pads. Those muthas were pure scripture.