I used to customise the hell out of tcsh, zsh... until I started using fish, which just has sane defaults.

What makes me reluctant to use fish is the fact that it's syntax is totally incompatible with bash and zsh.

Lets you use bash utilities from fish. So you can do things like `source` files and have it work.

Also I prefer to use Fish only as an interactive shell, actual scripts can stay bash.