Well, not always (don’t get depressed!) but if you are working on your instrument and you struggle, it is a good sign.
Because it means that you are aiming for something most people won’t achieve. They will actually give up. It means that you reached a point where you can level up your game. When this happens, it is a good sign, you are on the right path.
You have to hold on for a bit more time, find a solution to get to the other side (and I may be able to help you).
Never give up and you will be good, real good. You will make a difference.
It is tough I know. But it is worth it. 1000%.
So what are you going to do?