Dating back to 3rd critical skill checks in D&D suck because a lot of skills are written as pass/fail.
Example: picking a lock. If we want to add criticals, a 1 breaks the lock; mostly okay, with the long acknowledged fringe problem of experts being incompetent 5% of the time. What does a natural 20 get? I adore opportunities to be creative, but there’s not a lot better than, “You did it perfectly.” A regular success earns that according to the rules, I don’t want to take it away. A speech about how cool and ninja the PC is can come off pretty cringey to me. The correct mechanical answer would be to let the 20 roll over to the next check because the PC’s in the zone or whatever. Not awful, but it doesn’t directly reward the player right when they rolled the 20, which is the occurrence we want to feel good. We’re also rewriting several rules at this point.
Meanwhile, PF2e baked degrees of success into everything. On a crit fail they break the lock, on a fail they leave traces of their fruitless efforts, on a success they get one success toward opening the lock while scuffing it up a little, and on a crit success they get two successes and leave the lock looking pristine. The players don’t feel cheated when they get a normal success and scuff up the lock. The 20 has some reward for most characters. The 1 has a setback, even a reasonable setback for an expert with a +25 trying to open the DC 10 lock on Grandma’s rickety shed.
I actually don’t mind pass/fail skill rolls in D&D or other games. Rolling a 20 is inherently satisfying to me. But I adore the DC+10 critical threshold for making a good build feel like it was time well spent, in or out of game. And since the natural 20/1 and critical rules are connected at the hip, I’ll gladly take them both.
Once in a blue moon, an impossible check can impress a scale of difficulty on the players.
D&D example: a player with a high bonus attempts an Arcana check to figure out an enchantment and rolls well, up to a natural 20. I let the players have their moment of joy. Then I make a big deal of telling them they don’t have any idea what’s up with this enchantment. I really talk up how weird/complicated/confusing/impenetrable the enchantment is.
I’d be trying to prompt emotions I want the players and PC to share. Frustration, inadequacy. The players would viscerally know they need to try a different approach.
And because I gave the check a decent chunk of game time, it has more narrative weight. An interactive skill check is more substantial in the player’s mind than a monologue on the task being impossible, particularly if it stands out because they fail that check despite a super high result.
It’s a niche scenario, I admit. Most of the time just don’t ask for the check.