Get some live distro first and check it out without installation. You will be able to test some basic desktop environments very easily. Most of the distros will have live image. Even better run it in a virtual machine and play around. Test KDE, Gnome, Cinnamon and XFCE. Look at some themes and plugins. I think customizing your desktop is a nice, visual way to see how flexible it all is and get the feel of how configuration files work. If you will like what you can achieve with a bit of work you will just keep going. If you will find it ‘stupid and useless’ it’s probably not for you.