Stop fretting or whining about how difficult that song or passage is.
Instead, start by finding or creating ten distinctly different ways to improve it. Even the smallest improvement counts. Do that, and not only have you improved your song, you’ve also gained ten new problem solving skills which can be applied to future musical challenges. Your violin practice time was a high payoff activity that will save countless hours of work moving forward.
When all is said and done you are:
1. A more skilled and thus more desirable musician
2. A more effective human being who has trained her brain to do high quality, creative work in any situation.
Music is transformative. Violin is transformative.