Now THIS is a real Swiss Army Man.
As someone has mentioned, “Pass” and “Fail” are not the only possible outcomes of any given roll. That’s why there are numbers on the dice besides 1 and 20.
Also, the GM doesn’t usually(and also shouldn’t, with everything else they need to keep track of) memorize every aspect of all their players’ character sheets - they don’t necessarily KNOW if the check is impossible to pass or fail.
I don’t know if 5th has that as an official rule or it’s a common house rule.
It’s mentioned somewhere in Chapter 8 of the DMG.
Magic should be powerful, yes, but non-magic users should be able to function.
I’ve always house ruled that it didn’t make sense for a character to fail at the thing they’re the best at.
House Ruled? That’s RAW. Crit Fails and successes only apply to attack rolls and death saves. And that’s how it should be.
My Warlock whose patron is her cat:
Correct.