Same here. I used it for about 3 days before I installed it on all my systems and permanently switched. For me, it was like the first time I learned a non-Latin language, and my eyes were opened to how much stuff I took for granted was completely arbitrary.

For example, here's how you write an autoloaded function "foo" in Fish: you make a file called "foo.fish" in its config directory. Inside that, you write "function foo ..." to implement it. There's no step 3. That's it.

Want to customize your shell prompt? Follow the process above to write a function called "fish_prompt" that uses normal scripting things like echo, pwd, git, or whatever to write your prompt to the screen. There's no step 2. That's it.

Fish was revelatory. Other shells of the same vintage feel hopelessly outdated to me now. For context, I was the maintainer of FreeBSD's "bash-completion" port for a few years way back when. It's not that I don't have experience with other shells. I have plenty. I just don't want to use any of the others now.