I am probably one of the last people to try to discourage a fellow writer from sharing his or her work with others.  After all, that's the nature of our work.  We express ourselves to be read and heard out by others.  However, I do offer some words of caution for writers who enter into this fellowship of expression without some discretion.

My first exposure to critique groups or sessions was as a youth through a UCLA writing course.  Naturally, being quite younger than my college-aged classmates, I was viewed as some sort of phenom for even being in the class.  Nevertheless, I dreaded the sessions where we would circle up and share with one another in order to be pummeled by feedback from our peers. 

Why?

A fellow writer may be honest with constructive criticism, but an envious or jealous writer may also offer some truly adversarial advice.  They may just believe that they are keeping you in your place or helping you to remain humble.  I don't believe that is my place or anyone else's to deem that I have a handle on the entirety of writing as a craft or a business.  I have some experiences and insights, but I do not know it all.  I suspect that there are plenty of writers in the same boat, too.

Here is some advice for those who gain and give feedback :

• Ask for what you want to receive back.  If you don't want a laundry list of what is wrong with it, ask for specific types of responses.  For instance, ask for responses to emotions stimulated by your poem or story.  Be specific or accept a wide variety of feedback that covers the expanse of writing.
• Give it out a bit at a time.  Don't dump a full manuscript on folks and expect people to read it.  Give out a chapter or an opening scene.  Read an opening line of your poem.  Give them something that they can digest and see how it hits them.  If it reaches your fellow writers, they will ask to read more or ask you what became of that  story.
•  Think reciprocity.  I know some believe in karma or fate, but let's face it.  One day the tables will be turned.  You will have to subject yourself to the same type of scrutiny by which you measured the writing of others.  Be tactful and professional when critiquing and offering feedback to your fellow writers. 
• Don't take it personal.  Be realistic.  Some folks are simply negative.  They cannot stand for someone else to be more talented or gifted than themselves.  Recognize that such people will pounce upon the slightest errorand harp on that as if the muses have sounded the trumpet or alarm that you have performed some blasphemous act of disobedience as a writer.  Let it go.  Do not allow that to cause you to stop writing.  use some discernment when dealing with people.  After all, it's only their opinion.  If everyone who reads it or hears says the same thing or something similar, then you need to recognize that you may have some work to do.  That's being realistic.