Here's my favorite tip: If you use bash, you can write bash on your prompt (duh). But this is one of the biggest reasons I stick with bash everywhere, as I am quite comfortable and experienced in bash and sometimes it's just easier to write things like `for i in *.mp3; do ffmpeg -i $i ...` etc. If it's re-usable, I write it to a bash script later.

That's vaccously true as you said isn't it? I write fish on my shell and then I can save it as a fish script. Worth noting that bash is much more portable and available by default, but if I'm going for portability I go straight to /bin/sh