It's rough and ruthless, but criticism saves you time. People aren't trying to be mean. They're just trying to keep you from banging your head into the same wall.
Scientists can't continue publishing the same paper over and over again. Apple can't just release another iPhone without drastic improvements. As they say, sameness destroys creativity.
Instead of giving up, what critical advice does is redirect you. Writes Tom Standage in Writing on the Wall:
“Adam Smith. He wrote much of his book in the British Coffee House, his base and postal address in London and a popular meeting place for Scottish intellectuals, among whom he circulated chapters of his book for criticism and comment.”
In search of a little audience, you get the feedback you need to keep iterating until we get it right. Naturally, the process is frustrating for all artists. Writes Fred Kaplan on John Coltrane's experimental determination.
In a backstage interview with Coltrane during intermission at the Stockholm concert, a local jazz DJ noted that some critics were finding his new sound “unbeautiful” and “angry,” then asked, “Do you feel angry?” Coltrane replied, in a gentle, deliberative tone, “No, I don’t,” adding, “The reason I play so many sounds, maybe it sounds angry, it’s because I’m trying so many things at one time, you see? I haven’t sorted them out. I have a whole bag of things that I’m trying to work through and get the one essential.”
The fear of messing up is good quality control. The feedback loop is a critical ingredient to success. Otherwise, you may just be making something that never sticks.