Terry Pratchett has a way of making the end of the world feel like a cozy, chaotic comedy of errors. Good Omens is a masterclass in "wicked humor." It takes the heavy concepts of the Four Horsemen and the Apocalypse and turns them into a mirror for human absurdity.
I enjoyed the iconic friendship of Aziraphale and Crowley, as well as the sharp feminist wit (the line about male authors writing about naked witches is iconic). However, I was particularly moved by the environmental subtext; the way the authors highlight the slow destruction of our world by human hands, often more effectively than the "official" demons do, was very impressive. This book has something for everyone. It is a perfect, wickedly funny read.
For me, it will always be one of those rare books that manages to be incredibly cynical about humanity while being deeply in love with it at the same time.