From Ray Dalio's "Principles," my favorite work of nonfiction —
... 40) Recognize that the inevitable responsible party is the person who bears the consequences of what is done. Because of this, the RP must choose wisely when delegating responsibilities to others, and he must incentivize and manage them appropriately. There is no escaping that. For example, you are the inevitable RP for taking care of your health because you’re the one who inevitably bears the consequences. If you’re sick, you might choose to delegate the responsibility of figuring out what do to about it to a doctor. However, it is your responsibility to pick the right doctor because you will bear the consequences of that decision. While it is, of course, also the doctor’s responsibility to handle the responsibilities that you delegate to him, you still need to make sure that his incentives are aligned with his responsibilities and that he is doing his job well. The inevitable responsible party can’t delegate all his responsibilities away and expect good outcomes, even in cases in which he has no expertise. So you can’t escape hiring and managing properly.
While the logic here is incredibly sound, the vast majority of people do not think this way.
It doesn't help that experts encourage you to delegate your authority to them, and specialized topics are confusing.
Dalio uses the health/doctor example, which is a good one. But here is another obvious one: if you're pursuing a legal case, it is absolutely up to you to plan your legal strategy, set your budget, interview attorneys while communicating your expectations and plan, pick an attorney that "gets it" and communicate your expectations to him or her, and then manage and followup appropriately.
Most people, in a legal situation, feel intimidated and delegate to their attorney. But at the end of the day, the attorney is paid by their fees and the majority of attorneys will err on the side of accumulating more fees rather than less.
Not all of them. Perhaps 30% of attorneys will take a very sincere interest in maximizing the clients' outcome while minimizing fees spent, time, and potential aggravation. (This might be a generously high estimate.) But even if you know there's good attorneys out there who care about their clients and want to get things done quickly and efficiently, it's still up to you to find someone like that and get into a good working relationship with them.
This is, of course, obvious when written on paper.
But most people don't do it.
Here, some examples: you're in a class. Is it your responsibility or the teacher's to make sure you master all the material?
You're going out drinking. Can you count on your friends or the bar you're visiting to ensure you don't drink too much and get sick or in a compromised situation?
You're going to Las Vegas. Who needs to ensure you don't lose too much money, you or the casino? Does the casino care about you?
You go to the doctor and get a prescription. Who needs to research the current state of the medicine, the effectiveness rates, and side effects to monitor them?
As Dalio says,
"...the inevitable responsible party is the person who bears the consequences of what is done."
It's axiomatically true, but almost no-one operates that way. You don't know the material? Well, get familiar with it quickly, at least enough to evaluate if the expert you're working with is good and what their track record is. If you bear the consequences, you're the responsible party.