It's funny, because I have completely the opposite view: stop telling people stuff is difficult! If people think what they're about to learn is supposed to be "hard", they're going to give up faster and be intellectually lazy. "Oh, I just can't figure it out because it's
hard."
I've found this to be particularly important with things that are fundamentally simple but very abstract. You can teach people quite a bit of advanced mathematics if you don't tell them it's supposed to be difficult; but if you start out by mentioning that it's graduate-level algebra or something, they just shut down and don't even try.
I think this is a big part of the "monad problem", coincidentally. People don't understand monads because everyone says they're impossible to understand. When I came at them, I expected something complex and obscure. I couldn't see their actual simplicity—they have a tiny definition, after all—because of my expectations. On the other hand, when I went to learn about arrows, which are a similarly abstract concept, I didn't have nearly the same difficulties because I wasn't expecting anything and could take the definition as it is. I had a decent understanding of arrows before a decent understanding of monads, which is a shame because I don't really like arrows!
Now, I suppose that this doesn't mean you should call everything "easy", but you should definitely not perpetuate the idea that things are difficult! (Unless, I suppose, you want to intimidate people rather than teach them.)