Personally I like to think about and keep in mind some of the things I tried and gave up on in my earlier years. Some of them I regret having done so.
So when I get discouraged I just think out loud ” if I give up I’ll regret it later”. Then I go back to a piece that I play well and play it in a kind of Zen mode. Then I try to remember when I could not play it that well. This helps me remember that I AM making progress. Then I map out a plan for the next day to learn one new phrase or tune fragment. Something simple but satisfying. Then I leave it alone till then and try not to think about it at all. The next day when I pick up the violin I feel fresh and ready to be inspired.
Playing music is a worthwhile endeavor. It gives pleasure and builds character. In the words of an employer I had when I was an apprentice….” If it was easy anyone could do it”.