The quote from Stephen King’s On Writing is pretty powerful. Stephen King, one of the world’s most well known author (I won’t say popular because a fair amount of people don’t like his work… but they do know his name), was once ashamed of his own writing.
I have spent a good many years since— too many, I think— being ashamed about what I write. I think I was forty before I realized that almost every writer of fiction and poetry who has ever published a line has been accused by someone of wasting his or her God-given talent. If you write (or paint or dance or sculpt or sing, I suppose), someone will try to make you feel lousy about it, that’s all.
King, Stephen. On Writing: A Memoir Of The Craft (p. 50).
I’ll admit, when people rip apart my writing sentence by sentence in workshops–it is occasionally physically painful. Considering all the work that goes into a piece before it meets Beta readers and all the experiences which are included in the work, it is very hard to hear that any part of it is not up to par.
The workshoppers don’t mean to make you feel lousy and so I don’t think the lousy feeling about your work actually comes from them. It really comes from you. If you are proud of your work, in the long run, that’s all that really matters.
With the exception of spelling and grammatical errors, of course.
In the end, if you believe the critics who say it was a waste of time, then it was.