Ubik was intentionally hilarious, with the never-fully-explained-but-there-you-go eye-eater, and the briefcase psychiatrist intended to drive you insane! (Or maybe that was from 3 Stigmata?)
Mark Weiser told me that Ubik was the inspiration of the term he coined, "Ubiquitous Computing"!
https://news.ycombinator.com/item?id=42790807
The Computer for the 21st Century:
https://www.youtube.com/watch?v=CkHALBOqn7s
I also loved The Weapon Shops of Isher, with the parallel universes and third eyes.