I'm the same way! I try to get good at something, and then immediately move on. I am the best at nothing, and better than almost no one. But I am the only person I know that can write code, swordfight, surf, use a ham radio, play a handful of instruments, build things out of electronics, draw and paint, shoot, blacksmith, and blow glass (all at the same time -- just kidding)! I make myself very happy by being able to try something and then practicing until I get "good" in my own opinion. It's absolutely true that up against pros I am pretty terrible! I have also come to understand over the years that this is a byproduct of having a hacker mentality. I am loathe to use that word in reference to anything I am or anything I do, but that's just what I see. Hackers are curious creatures, and so it follows that they can do a lot of things.
It's often really hard to judge how skilled you are at something. https://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect is overblown, but being able to say do a crappy weld in 4 hours that a competent person can do better in 15 minutes is often just dangerous. Many a handyman has caused 20,000+$ worth of damages or gotten someone injured.
That said, hobbies don't need to be productive and half assing something is often good enough. Yes, a simple wedge doorstop may damage the door, but well sometimes that's just not an issue.
