Once on Linux, I didn't even bother to install a file manager at all, I just kept using the terminal. My environment consisted in Openbox as a window manager, rxvt-unicode as a terminal with Bash as a shell, and then mostly Emacs and Firefox (considering only graphical programs).
A few years ago, maybe 2 or 3 I'm not sure, I decided to try to experience Linux the way "muggles" do, because I was always telling people to use it but I actually never properly used what they would if they followed my advice, i.e., Gnome or KDE. So I read a bit, compared the two, and decided to give a try to KDE.
It was a bit of a pain at the beginning, so my first move was to configure everything so that my usual key bindings worked again, but I quickly found that I could be as efficient and at ease as I was before using KDE Apps as they were intended to be used (I even switched from doing my emails in Emacs to using a graphical email client!).
Switching from managing files in the terminal to using Dolphin has been an amazing experience. Dolphin is probably one of my favorite piece of software today. And for things that are better done using a shell, you have a terminal at your fingertips anytime anywhere with all your settings from Konsole (the actual terminal app) thanks to the fantastic KParts framework. It even works transparently with remote mount over ftps thanks to KIO. Truly this is amazing.
It made me love a file manager, which is not something that I would have thought possible a few years back, or the years before that.
Nowadays I'm slowly switching from Emacs to Kate (this is a bit hard and has lead me to become a small KDE contributor to improve Kate and the underlying KTextEditor ^^).