Here's some advice I have learned due to some old toxic friend who are thankfully not my friends anymore, since I decided to leave them:

Don't criticize someone's work if they didn't ask for it, they won't be in a mindset to hear mistakes about their art. If you criticize someone's art without them asking for it, they will most likely take it personally. And only give constructive criticism. My toxic friends did that, but to be honest, what they both said wasn't constructive criticism at all, they were just insults. They said that if I didn't take criticism that I wouldn't improve, well, for their information, I was already content with where I was, it felt like they were saying that I shouldn't be proud of my art, especially with how I draw blood. Did I ever criticize their art without them asking? No, I did not, even if I thought there was a lot to improve on.
Those two would act like they were better than me too, and the younger one even said she was more mature than us and then proceeds to say immature and inappropriate things, saying that in an argument whilst the rest of us were trying to just peacefully express our personal opinions, they just called is dumb and all that crap, like dude we didn't want to argue and you started it. Heck, they didn't even seem to care when I wrote a long message as to why I wanted to leave. They even insulted my actual friend just because she was the oldest of the group, calling her certain things that she isn't at all. Sorry I kinda started rambling lol, but in conclusion; don't criticize someone's art if they didn't ask for it, and if they do, only give constructive criticism.
Those two also didn't even put what they said I should improve on to their own work (mind you they also said I should do, instead of could).
Lol just thinking about them again makes me so mad