As a militant atheist, I have to say Daoism surprised me when I first started learning about it because it's one of the few religions that actually makes a decent amount of sense. That's because it's not really a religion, but more of a philosophy of life (well, some people have made an organized religion with supernatural elements out of it, but they've ventured a ways away from the original philosophy of Laozi and Zhuangzi). Daoism isn't about gods or souls or rituals; it's about living life the right way, right here right now in the real world.