How to disable animations in Ubuntu 17.10 or 18.04?

While animations are nice and eye-catchy, after awhile they might be annoying. To disable animations first install Gnome Tweak Tool:

sudo apt install gnome-tweak-tool

Then launch tool either from command line by running gnome-tweak-tool or by using dash and searching for Tweak.

On the first tab Appearance there is a toggle switch Animations. That's it!