There is also the question of whether to share in a group or hide in a room. So many of us worry that if we share someone out there will either steal our work or pirate it. I personally don't worry, if someone pirated my work I would wonder why they chose THAT book and not something better (I, personally, still wonder why anyone would want to read my stuff, but I have self-esteem issues, and I'm incredibly happy when I find out that not only has someone read my stuff, but they have an opinion about it!). If someone steals my work, I know how to sue, and I know how copyright laws work, so that's covered too.
The problem for me, in regards to sharing with a group, is really twofold. I am not always good in social situations. I shake and tremble and my voice warbles when I talk. I get red and feel hot. I worry that someone will start throwing food at me because I am just that terrible. Then I worry that what I am sharing, the words that have come from my brain first and my heart second, will not be interesting enough to attract the attention of anyone listening. I am afraid that I will read my first, or second, or fifth draft and someone will say, "ew, no one should read this, EVER." This, however, has happened to me. I was kicked out of a writer's group and one of the other writer's told me that he felt my work was crap and the world shouldn't be subjected to my crap because it was destructive and horrible. I have never found a way to push past those words, so I write, I write and write and write and hope that people like what I write.
Honestly, no writer, no matter how bad and no matter what the subject, should be told that their work is destructive and that they should give up writing to save society from the perverse horror they have written. All writers should be taught and if there is a serious problem, they should be steered in another direction. No one should ever be belittled, not in a writer's group and not in a book or story review. The world out there tends to forget that there are people behind those stories, people with feelings and ambitions and goals.
A writer should feel safe in a writer's group, safe to explore and develop and even to offend. A writer's group can help new writer's learn the craft, and learn to schedule time, and they can help others grow and expand.
I no longer worry about offending anyone, I'm writing about zombies, serial killers, the death of children, and I've destroyed the life on one ten-year-old in my books. I can't worry that the violent sex, or brutal torture, or tasting of human flesh is going to put anyone off my books. I write horror, not books set in happy dancing bunny land. My main zombie character likes Pearl Jam and sad songs, my serial killer loves everything that has a good beat to kill to, my other characters like a variety of music depending on their moods. I write in coffee shops, at the kitchen table, and if it's sunny outside I grab my notebook (yes I write longhand) and sit under a tree with a soda and a snack.
So writer's, write. If you're new, write. If you've been writing a while, continue to write. If you've only written poems and want to write stories, go ahead and write it. And as for those reviews - don't let the bad ones hurt. Sure they sting, but more like a splinter not a sword slash.