Maxperson
Morkus from Orkus
That is not so. Are you a Dungeon Master or a Dungeon Follower? The rules are tools that serve the DM, not the other way around.
I'm a DM. One difference between you and I is that can admit when I fudge or house rule the game. I do so all the time. The rules serve me, but they are still rules. The way you disregard them, you might as well not bother buying the books at all and just wing it.
The rules cannot tell you there is uncertainty or that they must be used in a particular instance. The DM's judgment comes first and then, if he or she decides there is uncertainty, the rules can be brought into play to resolve it.
This is not how you play D&D. I've read the books. Not in any edition, including 5e, does it say that the rules are not in play unless the DM decides uncertainty is present. It's your playstyle addition to the game.