When I wrote my thesis for my bachelor's degree, I had to submit the paper and code. I was fortunate to have an incredibly helpful supervisor, who told me in the beginning to always ask for help when I'm stuck. Also, he would review a chapter picked by me like he would when he grades the paper. I asked him to review the chapter that I was most insecure about. The review came back with almost everything with a mark on it. Literally everything. Commas, typos, semantics, grammar, content. Every free white space on the page had some remark about what was wrong in some section. I was a bit shocked at first, since I knew I had to rewrite the entire chapter again probably and I only had a bit of time left. Then he said something that I remembered until today:
This is by the way just feedback. You can accept it or you can ignore it. Both are fine with me. I just wrote my thoughts down. Do not stress about it, the chapter is still fine.
I didn't know I learned a very good lesson for the future. When you ask someone for feedback, you can either accept or ignore it, but you cannot argue with it. It's that person's impression. I asked him for his professional opinion and he gave it to me crystal clear. I also at the time didn't know how important that principle would be for the future.
Of course I wrote the entire chapter again. Later on I realized that it's helpful to me to distinguish between feedback and criticism. Feedback is a way to improve, criticism is a way to judge. However, both can be helpful. There is positive and negative, constructive and unconstructive feedback and criticism.
Example: Let's say you've created a painting. You have painted before, so you're not a total beginner, however you are far from being a professional artist. After you've finished your painting you ask for feedback from various people.
Constructive feedback is the most helpful to you, since it not only tells you what is positive or negative but also why. Constructive feedback, either positive or negative, should probably never be ignored. Unconstructive feedback can still be helpful as it just shows the initial impression of something you did. However, unconstructive feedback also highly depends on the person who gives it to you. If "Cool painting" comes from a professional artist, this will definitely show you that you've done something cool. When it comes from someone who doesn't understand anything about art, it will not be helpful and can likely just be discarded.
Example: You put your painting in a gallery. You put it up for all people to see. You overheard a couple of people talking about your painting.
Criticizing is easy. You simply just say what you think without worrying about the implications. Although there are professional critics, we should always remember the wise words of food critic Anton Ego from the movie "Ratatouille":
In many ways, the work of a critic is easy. We risk very little, yet enjoy a position over those who offer up their work and their selves to our judgment. We thrive on negative criticism, which is fun to write and to read. But the bitter truth we critics must face is that, in the grand scheme of things, the average piece of junk is probably more meaningful than our criticism designating it so.
What this tells you is that honesty in criticism is the key to offering valuable and constructive criticism. In my own experience, constructive criticism pinpoints exactly what is good or bad and if the latter, also offering a possible alternative (Maybe the painting's better in black and white). Unconstructive criticism could be equated to the way people generally feel. Like unconstructive feedback, unconstructive criticism will give you just the general impression of people of your work. So what's the difference?
Feedback is asked for, criticism is given.
It greatly matters who is giving feedback or criticism. When you ask for feedback from a friend or your parents, they will probably give you positive feedback instead of completely trashing your work. If you need support, this is the way to go. However, when you ask a professional for feedback, you should expect to get insights into what you could improve on. Knowing that you cannot argue with their feedback is crucial, since it is in the end just their opinion, whether informed or uninformed. This gives you the power to reasonably accept or ignore any feedback you receive. (If your boss tells you in your yearly feedback meeting that you shouldn't always arrive late, that's probably something you shouldn't ignore).
Criticism on the other hand is just given to you, without you asking or wanting it. This is where not caring has its origin. When receiving criticism, it is helpful to have an understanding of the environment where it is given. If it comes from anonymous people it will never have the same weight to it as a person standing next to you and saying: "Yeah you should probably paint something else." While all negative criticism can easily be discarded (the haters!), if this is 80% of all criticism one receives, it might be worth looking into what exactly is so horrible. Also, when you receive criticism from a very knowledgeable person in the field, it may also be worth looking into.
As a last example: What I love to do when building user interfaces is to get the chance of observing the people using it. Especially if they're the average user, it will tell me a lot about what can be improved since fresh eyes can be more critical.
As a last note: None of this is founded in any scientific research. It's a successful mental model for me to deal with situations where I receive feedback or criticism.