I mostly want to learn artistic skills, like painting and playing instruments. I can tickle some black ink on a canvas and I can rattle out "Good Riddance" on a guitar, but that's about it. But I currently have no time to learn those particular skills, because I've put others as higher priority, like writing and game design. Perhaps if I live forever, I can swap out my current artistry in a few decades with those others. But if we're talking academics, I'd like to be able to learn physics better. I have a layman's understanding, but so many concepts are so mathematical and abstract that I can't wrap my brain around them, or when I can, I can't retain them. I once understood eleven-dimensional string theory, but I lost that knowledge about an hour after I grasped it.