Sayings I don't like: If you can dream it you can do it

I've seen the line "if you can dream it you can do it" attributed to various people.  I think it's stupid.

First of all, it is obviously incorrect.  I sometimes dream I can fly like a bird just by flapping my arms.  I can't. No matter much a human tries to fly, humans can't do that.

However, even if we remove things that are physically impossible, it's still wrong. I can dream about winning Powerball. But I can't do it, in all likelihood, and buying tickets is pretty much a waste of money.

So, let's eliminate things that depend entirely on luck.  It's still wrong. I can dream about being able to do math like Ramanujan or play chess like Magnus Carlsen.  I can't. And no amount of practice or effort will make me able to do so. And that's true for well over 99% of the human race. Almost no one has the native talent to be a world class mathematician or chess player or, really anything else.

It's not just wrong. It's pernicious. It sets up unrealistic expectations that are doomed to fail. Failure feels bad. It's demoralizing. It can keep you from doing the things that you really can do.