Six Feet Under is my favourite show EVER, aside from Dexter. The whole theme of the show just rings so true, honest & gritty and I relate so much, having dealt with a great deal of loss early in my life.
The idea of forbidden love is found between Nicholas and Etta. They come from families who are at war, as well as from different time periods. In Nicholas' time a man and a woman of different races was also looked down on.