I once read that all anyone can expect out of life are happy moments, not happiness. The ending was a happy MOMENT that was well-earned by the fictional characters, and esp. by the audience who has followed them. The two characters said a lot of belatedly kind things to each other five years after the fact, and hugged in the final scene. Wow—what “happiness overkill” to ruin a series (sarcasm). I feel zero need to have The Killing ‘teach me a life lesson’ about the darkness of life in its conclusion, it has done that for four years. I for sure don’t regard it as horribly damaged because it allowed some light in it’s last five minutes. My guess is that if the series had ended darkly, this author would have been just as happy to write lots of negative paragraphs on why that was wrong, too.