I'm going to ignore my best friend of 4 years to hang out with some new friends.
Why would you ignore your best friend for new friends?
I feel like my friend is holding me back and I don't like it. I must spread my wings and do other things too.
It really isn't nice of you to ignore your friend. Your best friend, who you've known for a long time, should take precedence over your new friends. Don't ignore your best friend like that.
No, my old friend is a loser, I'm over them.
Ghosting them is the rudest way possible to end it. They were once your good friend, so don't you feel you owe it to them to at least say goodbye? It will give you closure.