I catch your drift on the common sense is just forgotten learning. That's probably closer to the truth than we'd all like to be told. Thing is, I don't think you've contradicted me re: too much confidence in your abilities.
It's basically like rolling Nat20s in Dungeons and Dragons. Eventually everyone runs into a situation they need to get out of, A.K.A 'roll to save' (I think that's the correct term). You can reduce to times you need to 'roll a nat 20' by improving your skills, knowledge, and gear. Or you can think of those things as removing sides from the die, making it more likely you can get a positive result. When you're accomplished and capable outdoors, though, whatever puts you on your ass is probably not just a paper cut. A higher ceiling of competence drags the floor of consequences up with it.
Even more so than that though, the best way to stay safe is to not put yourself in situations where you need to "roll a nat 20" to save yourself or avoid something bad happening. I.e "don't let your guard down" is a preventative, and the saying goes 'something something an ounce of it...'