In response to @poojas Monday Madness card about our favorite anime ending theme songs, I had to think pretty hard. Harder than I thought I would. I'm generally an impatient type of person, and I'm far too eager to skip the ending credits to move right on to the next episode.
That being said, I do recall one ending that really stuck out to me: The ending song to Elfen Lied, "Be Your Girl".
Elfen Lied, for those who haven't watched it, is a pretty messed up romance/horror anime about Lucy, a Diclonius (meaning she is a kind of mutant with horns and "vectors" - invisible arms capable of cutting through basically anything) and her relationship with a human boy named Kohta.
The anime is super violent and vulgar, though also really cute at times and often funny. In any case, the ending song (above) really catches my attention because of the way it kind of sadly encapsulates everything about the anime very succinctly. It's called "Be Your Girl" and that's apt because that's a big part of Lucy's story. She wants to be Kohta's girl. but it's also more than that. The aria of it is so sorrowful, so sad, like the emotions Lucy must feel.
The song provides a great contrast to the high intensity of the anime, and I totally suggest watching it if you haven't yet.