Lennier was a tragedy, but so so poignant.
I've seen the series 4 times in total now, maybe 5. I introduced my girlfriend to it, she loves it too. After her first viewing, during the last two episodes, we were both crying because of, and for, Lennier.
So during her second time viewing the series, the moment Lennier walks into screen for the first time....she was just crying again, knowing what was coming.
Hell, during the episode in DS9 where Bill Mummy has a part, she actually got a bit chocked.