Perhaps, the cruelest thing ever done to the humanity was making it believe.
Believe in all sorts of things.
Believe that tomorrow they will wake up in a different, better world, whereas in fact it doesn’t change this way overnight. Hardly for the better, at least.
Believe that our path is predestined and we cannot (shouldn’t) do anything to change it.
Believe that there are good and bad, so fixed and so easy to distinguish, whereas they are well mixed up together and hugely depend on all sorts of context (personally, I think that everyone defines for themselves at some point what is right and what is wrong). Believe in necessity of living “by the book”, living up to everyone’s expectations. Play the role instead of being themselves, live in a way one may want to.
Believe that someone or something cares enough to help us somehow, to read our minds, to notice the (sub)conscious signs, whereas we are on our own.
Believe in miracles that seldom happen.
Believe in the simplicity of the overall notion of the world, with everything being categorized and scientifically discovered, whereas the reality is far from that.
Any belief is a fragile little thing, poisoning the heart and mind, and then exploding at some point, making its bearer a little bit more dead inside.