First off, here is an entire article about the fonts in GNOME 3, and it even promises to tell you how to change the fonts: Fonts in GNOME 3: Cantarell, Tweaking, and Trailblazing.
How do you change the fonts? Well, you fire off commandline incantations like:
gsettings set org.gnome.desktop.interface font-name "Dejavu Serif 10"
Hello, GNOME 3, this is 1995 calling, we want you to stop stealing our great ~/.Xresources text-file way of configuring fonts!!
I am all for sensible defaults and not allowing just anything to be changed, so as not to confuse people, but NOT respecting my previous font settings AND only allowing me to change the fonts - a very visual thing - from the fucking commandline is INSANE.
Tweak Advanced Settings
By searching for how to change the fonts in GNOME 3, I found "gnome-tweak-tool" which is found in the menu after installation as "Tweak Advanced Settings".
File Manager - getting desktop icons back
Under "File Manager", there is a switch to get my icons on the desktop back. Thank you.
Next Advanced entry is "Fonts". Phew.
Under the "Interface" part, ah good, this is where I can change to the "Simple" theme which makes buttons, toolbars and scrollbars look like I chose them to look before GNOME 3 ignored my settings and changed them to the new default.
No, it isn't. The only choices are the new default "Adwaita" and something that looks like Windows 2000 called "Raleigh" and then the high/low contrast ones for people with eyesight problems. Where did Simple go?!?
Under "Shell" I found some options about closing the lid of my laptop. Well, this is a desktop, there is no lid.
Eerily empty. It doesn't even say that there are no extensions currently. I am expecting a crash any time now (hasn't happened yet, I must add).
Ah, here is another place to change the theme. Maybe my Simple buttons hide here? I can, indeed, change "Current theme" to "Simple", but it doesn't change anything. Probably because I have changed to another window manager than the default (automatically reinstating) one.