In my example, I was not talking about taking 10. I was referring to a very skilled champion soldier who has killed many big enemies... he has +10 skill and trips on the stairs twice during a very epic battle simply because he got unlucky and rolled a 1 two times. Yes. I absolutely advocate changing such rules when they make players feel like their super tough champion warriors are morons who trip on their own shoelaces and can't even ascend a staircase during a very important battle.

On the flip side, imagine being in combat and you can't ever miss an enemy no matter what you roll. How boring would that combat be? 0 chance of missing.

Or, better yet, take it to the other end. 0 chance of hitting. The enemy has 27 AC because of buffs and such, and you can't hit them because you can't even roll a 20 and hit with your bonuses. GG. Thanks for playing. You're dead, no matter what.

The point of the Nat 20/Nat 1 for combat is so that you never get stuck in a critical combat situation that you can't win or that you can't lose. The point of not having this for skill checks and other rolls is so that you CAN have situations that are impossible for characters. That's my point.

Imagine fighting a boss enemy and all your allies are incapacitated. The boss only has 5 HP remaining, but she's buffed herself so her AC is 24. Your To Hit is +3. 0% chance of winning. It's all down to you, but you can't kill her because your To Hit is only +3.

And again, imagine someone with 0 skill at picking locks. In fact, they have a -1 because their ability score is 8. Rolls a Nat 20 and succeeds in picking a lock that has a DC of 25. Meanwhile, the expert lockpicker in your party with +2 Proficiency and +2 for Expertise and +3 for ability score bonus - so a +7 in total - fails to pick a lock with DC 5 because they rolled a 1. The lock is a baby lock you can twist with a screwdriver, but - well, you know, you rolled a 1, so you stand there like a moron staring at the screwdriver lock while scratching your head. Meanwhile, your buddy with the -1 rolls a 6 and succeeds. "Um. Having an off day, Expert? Did you have a brain fart? Can't pick a screwdriver lock you could actually use your fingernail to also twist?"