I get my share of requests--to please read and give feedback on someone's script or play or story or article. To be very honest, I am never too thrilled to get these requests. First, since so much of my own day is spent in writing (email queries, business emails, my own scripts, my book), when I read, I like to read for pleasure. I like to pick and choose what I am going to read. A friend/acquaintance's work almost always feels like yet another "to do" on my list. Secondly, I am not a critic, and always refrain from saying negative things, even if a critic might deem such negative things to be richly deserved! So my feedback is hardly likely to be constructive. I have very vivid memories of my girlhood in India, when a classmate hounded me for "honest criticism" on her short story. I said one mildly negative thing (after she pushed and persisted)--that the piece felt just a tad long. That was the end of the friendship.
On the flip side of the coin, I never pass my work around to my friends and acquaintances, asking for feedback. Whether one wants it or not, one always gets more than enough "feedback" when one starts to circulate one's work to agents, representatives, book editors, publishers, producers, production companies, actors, etc. I've found that if there are genuine cracks in one's work that need to be fixed, they make themselves known, with time. Your own inner voice will nudge you, and, if you slow down enough to listen, tell how how to fix it!