Haskell, guarantees and pusillanimity

Many times in the course of my Haskell apprenticeship, I've had conversations of the following form:

Me: I want to do X in Haskell, but the obvious thing doesn't work. How do I do it?
Sensei (usually Duncan or totherme): Oh no, you can't do that! If you could do that, then you could have a transperambic Papadopolous twisted asiatic sine-curve freezeglargle Windhoek chromium bebop.
Me: Er, come again?
Sensei: well, [note of horror creeps into voice] it would be really bad! You could get [thing that doesn't sound all that bad, really].
Me: But that's a good thing/Nah, that would never happen/would never happen in real-world code/that's a price I'd gladly pay.

( Here's why I think this happens - Haskellers prefer guarantees to expressivity )

So, Haskellers: am I right? More importantly, is this widely known? Is it explicitly written down anywhere? (The second article comes very close, but I don't think it gets there in full generality). Because it strikes me that it would be a good thing to tell newbies as early as possible, and also a good thing to have it explicit so it can be appealed to, or (better) debated.