For example, I just recently tried Debian for the first time after using Ubuntu for several years. I was shocked at how alike they are (at least, for the 5 minutes I used it.) So my question is, what is it that actually makes Ubuntu different than Debian? Yes, it has things like the Software repository or even package management, but then that leads to another (possibly stupid) question: are programs/packages the only thing that separates Linux distros?
Another way I've looked at it is the fact that you can swap out Window Managers/Desktop Environments. Like Crunchbang is like Ubuntu but with Openbox instead of GNOME, and my question is, if you downloaded Ubuntu, removed GNOME, and installed Openbox, would you have Crunchbang? Yeah, there's obviously other bundled apps that separate the two (like Conky), but it's still the principle of the thing: is it just a bunch of pieces that make up the whole thing?
I guess it's kind of like the Ship of Theseus (which I'm going to admit, I'm not going to claim that I know anything about, except passing reference). If I remove GNOME, is it still Ubuntu? If I remove the Firefox and replace it with Epiphany, is it still Ubuntu? How many pieces would I have to remove to turn it from Ubuntu to Debian? Or can you not do that?
It's mostly from my lack of knowledge on the subject. I still don't really grasp the difference between Window Managers and Desktop Environments, and the same goes with the bigger picture, i.e., the Operating System itself. What makes all these derivatives different than their parents? Or to go one step further, what really makes two distros different if they run the same desktop environment and have the same programs?
I guess this came up for me when I keep trying all of these different variations, and I'd find all of these that use GNOME or KDE, and I've just started to wonder, since every one has KDE and every one can have the same programs (Firefox, OpenOffice, etc), why do multiple variations even exist? What's the point? I'm trying to find my favorite and also a replacement for Jolicloud for me EEE, and I'm just having troubles distinguishing differences for the more "complete" varieties.