hmm, what about forgetting a terrible truth? or something awful that was done to you? Sorry, trying to find some neutral reason someone would pray to her.
I think I actually read about it once that this is exactly the reasons why non-evil people pray to Shar. She is the goddess of Loss - you pray to her when you lost someone dear to you, when you had trauma and similiar. You pray to hear, so that she takes the pain away from you, when it is too much to endure.
Iirc, there used to be a neutral order of Sharrans that focuses on that aspect. Helping the desperate to forget what hurts them.
Her wishing to end all existence is not *that* common knowledge.
