Good ol' critique. Something which quite a lot of artists dread, including myself.
The thing with critique is that if done correctly, it is actually very healthy. A necessity, if I were to take it that far. An artist who doesn't critique at least their own work is not liable to get very far, in my opinion.
It's not to say that critique can't be done poorly. It most certainly can, both critiques given by others and critiques towards yourself. In fact, I think that terrible critique is the reason why we're so afraid of it in the first place.
I want to talk about critique which is actually constructive, and how critique is misused and misinterpreted to the detriment of artists. However, this can apply to a whole host of other things as well, including self-improvement in general.
It's very important to note the difference between constructive and non-constructive critique. In my opinion, a good constructive critique points out something that the artist can take action with right now. If an experienced artist were to point out every single flaw that a beginner artist has made in their piece, then it would be beyond overwhelming. Not only that, but constructive critique should give steps on how to actually fix it, rather than just telling them what's wrong and leaving it at that.
This type of critique is practically the antithesis of non-constructive critique. Honestly, critique should immediately imply it to be constructive, because non-constructive critique is practically an oxymoronic term.
Non-constructive critique almost devolves into nitpicking, and at the very worst it turns into pure insult. Even if they point something out that is definitely true about the piece, it's near useless if there are no pointers on how to fix it. Some examples of non-constructive critique given by others include "X looks off", and "this looks bad". Like, ok? Now what?
The normal defence to this is the saying that I often hear: "a person who doesn't cook can tell if something tastes bad". Of course that's a given, but only an experienced chef will be able to tell that it's bad and knows how to fix it also. That last part is very important for the chef who's ability is in question to actually improve, and it's practically the basis for founded critique.
A better representation of this horribly misused quote would be "a person who doesn't cook can tell if something tastes bad, but a person who does cook can tell the chef how to actually cook better."
Applying this to art, an average person can tell that something doesn't look right with a piece, but an experienced artist can give pointers on how to actually fix it. Now, which is constructive critique: a person who says "this looks bad", or a person who says "this looks bad, but you can do X, Y, and Z to fix it"? One points out the obvious, but another points out the obvious and actually helps the situation. Constructive critique builds up (hence the word constructive), but non-constructive critique only tears down. At its best non-constructive critique is an objective observation (a pointer whether something "looks off", which is at least something), and at its worst it's purely dealt to tear flesh.
Now this is where it gets spicy: self-critique.
Since I'm a self-taught artist, I'm placed in a situation where I have to critique my own work. It's inevitable. Like typical critique aimed at other people, self-critique can be done well, or badly. The greatest hurdle with self-critique is that it's hard to be objective with ourselves.
Like what I've written above about constructive and non-constructive critique, it's important to apply that when looking at one's own work as well. Constructive critique should be done in the same way as you would critique towards other people's work.
For non-constructive self-critique, the hallmark of that is obscurity, and added baggage. These can also apply to critiques given towards others as well.
Obscurity is like the example I mentioned in the last section, where you simply state "this looks bad" without pointing out what needs work. If the whole thing looks bad, it won't be of any help to point that out as it doesn't give any real direction. It's best to pick out one specific thing that needs work and work on that. The more specific, the better. It could be perspective issues, anatomy, colour choice, whatever, but please don't let it be "it's all garbage". That's certainly not going to help.
And I say to only point out one thing because there is a subset of people who know exactly what's wrong, but they number their faults as if they were raking in debt that they cannot pay. They see a hundred and one different things that's wrong with their work, but that'll only lead to a huge burden that they cannot possibly tackle all at once. It's best to focus on one weakness and work on that, rather than drowning one's self with a mountain of shortcomings.
The other pillar of non-constructive self-critique, which I've called added baggage, is basically creating greater implications from the result of one's work. You can say "X needs work" and that would be quite beneficial, but if you say "X needs work. man, I'm such a terrible artist", then there's unnecessary baggage that's emotionally weighing down the critique.
The dangerous thing about added baggage is that it almost always becomes the focal point. The focus isn't "X needs work, so I'm going to start fixing issue X", but rather "I'm such a terrible artist, why should I even bother?" Self-critique isn't really critique anymore, but rather it turns into self-insult, which is not good.
The opposite of that example holds true also: you can think of yourself to be so good at your work that you essentially become blind to your mistakes. The baggage in this case is ego, where a small victory suddenly is blown out of proportion, implying that you are somehow now "one of the greats". Of course, that illustration in itself is overly exaggerated, but it's still affects people in minute ways, and is something to watch out for.
Getting self-critiques right is very beneficial, because we are truly the only person who knows where we want to go, and actually has the power to improve ourselves. Though getting critiques from others is helpful, doing productive self-critiques will get you really far, if not all the way.
I want to leave this off with a small summary of what critique isn't. The word in itself has certain misinterprations that result in the justification of words that need not be exchanged, both towards others and towards yourself.
Insult: the most common form of non-critique out there. You know those people that say "if you can't handle critiques, then don't post your work online"? Yeah, they probably just rail on people's hard work for no good reason and call it "critique". That's like the parent who constantly nitpicks their child's artwork, when all the child wanted to do was show it to them.
It is important to note however that not all critique is meant to be an insult. Good critique is going to hurt regardless, but not all are intended for malice. This is why it's so hard to distinguish insult from critique: both hurt, but one is foundationally useless.
Ambiguous: something which is so general that it doesn't even help anyone. Saying "this looks bad" to an artist who's asking for critique is basically telling them that they're blind to their own mistakes. While we're not assuming that they aren't blind to them, it's still not helpful in the slightest.
A declaration of differing tastes: this is why critique is so hard to give. With everyone having differing tastes, it's very hard to give constructive advice without delineating into changing another person's artwork into something that suits more towards your tastes and not the artist's own tastes.
The controversy of "fixing art" on the dreaded bird app is basically this in its most toxic form, with a dash of self-righteousness and virtue signaling. But a majority of the time you'll see this in the form of "I wish you did Y instead of X", or "I don't like the look of this". It's not even a matter of whether something is technically wrong, but a matter of taste, which shouldn't be the driving force of critique.
This is not to say that I look down upon sharing opinions. If you have opinions about certain styles or whatever (I certainly do), then that's fine, but call it an opinion and not a critique. Labelling it as critique sort of implies objectivity, which leads people to take garbage from people who ought to be ignored, because they think that critiques have to be taken at face value no matter how bad it is.
This brings us to the most important aspect of critique, which is that it's entirely up to you if you want to take it or not. Critique becomes practically useless when it doesn't even align with the artist's goals and intentions. Imagine how useless it would be for a cartoonist to get the "critique" that their work doesn't look realistic. They're certainly not obliged to apply that to their work at all.
If I were to boil down how to take critique, it would be to take critique from people who you know are experienced, who you can trust and preferably those who know where you want to take your art. Of course, strangers can also give pretty decent critique, but from those aforementioned individuals you can at least guarantee that they're doing it for your own good and not to derail you or lead you to a dead end.