I can't stand my best and only friend anymore. I tried to explain what he's like but it couldn't fit the ask box. Basically he's a very good friend in my daily life, but as an artist I can't stand him. He thinks like a child when it comes to improving his art, and he even copied one of my artworks before and put it online. My question is what should I do? I don't want to loose the only person that I can talk to, at the same time I can't agree with the things he's doing.

it sounds like you should try to find some better friends, to be honest - you want to try to surround yourself with people who have similar goals and ideals… it’s okay to have him as a normal friend, but you really need to find some artist friends if that’s an important thing to you.  If you think that talking to him about your feelings is going to make you lose him as a friend, you need to ask yourself: is holding back on talking about this what I want to do? is this important to me? is it more important that I let him keep doing this, or that I’m able to speak my mind?

I hope this helps - I have been in a similar situation, though there were differences, and I just ended up moving away from caring about having IRL friends because I couldn’t see eye to eye with any of them.