Depends on the machine and… maybe other things. I used to think that, too, but on my current machines I can step backwards just fine.
It’s probably a much more intensive operation requiring processing a lot of the file from before and throwing away current buffers or something.
I don’t think I’ve found amazing things recently. Things worth using and things better than the alternative and things that are promising to maybe one day be great, yes.
But I’ll single out one little thing: dust. https://github.com/bootandy/dust
It’s like a killer combination of du and sort oneliners that actually shows me what I want to know: What’s the big stuff in this dir.