There's a certain amount of confidence building we all need in the work we do, especially juniors, especially recent hires and especially creative people who expose their work continuously, which is an exhausting and often terrifying thing to do.
That includes designers, but also developers, their code and their commit messages. Anyone who creates anything. If we make sharing it unpleasant we reduce the frequency with which people create and share.
The less autonomy we have over our own work the more it eats away at our motivation to keep going, be productive, enjoy what we do and experiment with new ideas that could be hugely successful and useful to the world.
People have criticised my less than perfect code and designs but I am and have always been all about the impact they could have, and there wasn't time to be obsessively meticulous over ratios or whether or not I used pixels to define spacing, especially over code that would and did get deleted later because the needs changed before the code ever needed to.
It really doesn't matter that it wasn't perfect from day one, like Google wasn't and still isn't. Creating things is a process that takes compassion and nurturing as it grows, not shooting down when it's not perfect the moment it's released. That's anxiety, it's infectious and it needs dealing with.
Some people seem unable to tolerate anything less than perfection, which means being driven by the fear of mistakes and moving so slowly you're getting almost nothing done.
In my experience the best way to get the best work from people is to draw it out with praise and encouragement, and rewarding the production of ideas rather than the level of perfection, people’s intelligence or their innate qualities. It takes longer and isn't as easy as pointing out the obvious flaws the moment you spot them, but it works much better in the long run.
Here's an interesting study on children that also applies to adults on how praising intelligence rather than effort undermines behaviour by driving children to choose performance orientated goals and tasks - that is, things that will make them look smart, rather than things that will allow them to grow and learn, things that may fail and make them look 'less intelligent' if they do. But it's those things that have the highest chance of making an impact.
It's not innate intelligence that gets results, it's sheer practice and pure chance, so the more you practice the more chance you have to produce something brilliant and when we're more critical than rewarding we block people, they stop enjoying work and they stop practicing.