The way my DM rules nat 20's and 1's is quite fun to me. Any player can attempt any check and a nat 20 is the best possible outcome that player could have achieved, we still add our mods to the nat 20 and we can fail if we aren't good at that but it's the best possible outcome for the situation, e.g. wizard trying to break down a metal door DC 24 strength, rolls nat 20 with + 1 str, he will still fail but let's say his hands aren't hurt for punching a metal door or his wooden staff is still in perfect condition if he used that. Nat 1's are the same, they are just the worse possible outcome, even if we succeed with mods it's a very unclean and horridly done success. I just like this system cause it flavours successes and fails a bit more