Ending ending ending!

Now that my NaNoWriMo is back on track, I'm taking a few minutes to post some updates here.
My NaNoWriMo novel is in English and it's going to have a sad ending. I'm not a fan of happy ending because of a few reasons.
First, happy endings make us less human, I'm not lying. Whenever a story ends happily, we stopped caring or thinking about the characters because we will think that, oh she/he is now in good hands and will live happily ever after. Readers will not feel the need to revisit the characters i.e think about all the 'what-ifs'.
Secondly, there is no happy ending in real life. Life is always full of ups and downs. You'll be happy for a while, then suddenly you receive news about an old friend who is diagnosed with a critical illness. Happiness and sadness are temporary. They are not suitable to become the endings that I will appreciate.
I prefer endings that will make me think and make up my own conclusion.