I wish it was easier to do music, 3D, and animation. Also that I could focus on art more instead of putting it off due to anxiety but that's a different subject.
I'm mostly annoyed that my brain does a good job at imagining anime OPs to my ideas but I can't even get myself to storyboard them, never mind what animating them would be like~.
I have five different songs I've imagined as Twelve Thousand's OP over the years, and while some reuse visuals, there's a lot of changes I've imagined over time and show the evolution of the story's feeling and my brain wants there to be animations of all of them...