It's no secret that one of the hardest things to master is learning how to take constructuve criticism. Even though it's the key to growing as a person, it's not super easy to listen to someone point out your flaws. Your first instinct may be to get defensive or deflect what the person is telling you but more often than not, someone that cares about you is not out to make you feel bad about yourself.
The goal of helpful criticism is to help you become a better you.
As people, we are constantly changing not only in age, but in our likes, dislikes, and traits. While the essential parts of your personality may still stay the same, you are supposed to learn new things and incorproate them in the way you live your life.
New experiences always bring new lessons, and there is often no way to learn some of them other than been exposed to them firsthand. Everyone slips up from time to time, but the true test of your character is how you bounce back from it. When discussing self-improvement, there is one important thing to keep in mind:
You can only change if you truly want to.
Hearing all the helpful advice in the world will do nothing for you unless you see the need for imrpovement within yourself and actively want to work towards it. No one can force you to evolve and even if they try, it won't stick unless you believe in it.
This also goes for other people in your life as well. If someone you care about is in desperate need of change, telling them over and over again is only effective if they need that need within themselves. Never be afraid to look at yourself and be open to changes because you may surprise yourself with how much happiness and positivity could result.