As a person who usually doesn't finish the full course of antibiotics if they're feeling healthy: Why does it matter?
Some of their children will be even more resistant. Some of their children will end up in someone else who, just like you, did not finish the course of antibiotics and, just like you, ended up being an incubator for a hardier, more antibiotic resistant strain.
Eventually, the children are completely resistant and they laugh in the face of antibiotics, and then people start dying. People you never met. People who might be generations down the line from you infected with a super-resistant strain that can be traced back to you and others like you.
It’s important not to use antibiotics if you don’t need them, and to complete the course if you do need them. Otherwise you’re selecting for strains of disease that are hard to cure.
The antibiotics that you took are useless against this new bacteria. You will have to seek other antibiotics.
Carry this on with multiple types of antibiotics, and you have a Big Problem.
Edit: Amazing that there are four responses to this question, all within a minute of each other!
Please, for the sake of society at large, complete any and all antibiotic/antiviral drug courses you are prescribed by your physician.
You can feel healthy before all of the bugs are dead. The ones that remain are more resistant than the ones that died. By lettimg them survive, the baseline next time is "somewhat resistant".
Each time, this happens, the survivors are more resistant.
You're basically breeding resistant bugs. Either kill them all or leave them alone.
It's good that he asked and now he will know why it's important and will do it.. It's a failure of education if intelligent and educated people are not aware of the consequences.
I wonder what other prescription instructions he disregards... drug interaction warnings? You don't get to disregard those just because you're not familiar with the biochemistry involved.
Or, what about, "Do not look into 1W laser with remaining good eye?" If you don't know what a laser is or why it might be bad to look into it, you either research the issue, or you follow those instructions blindly (pun intended). You don't blow them off and then ask HN why looking into class 4 lasers is bad after both your eyes are damaged.
It's good that they finally asked, though. It should have been asked a long time ago, and not on HN, I think that's the point of the downvotes.
Why shouldn't it be well explained? It's not like it's rare for doctors to prescribe things people don't really need, especially in this day and age, in the USA.
Almost everyone crosses the street when the light is red, but there is not a car in sight (and the view is clear). Many people will use perishable products after their guaranteed 'fresh until' period.
However, this also happens for instructions you don't actually know the reason for. People will mentally substitute a convenient reason. Take the antibiotics for 3 weeks? "Yeah, probably because it sometimes takes 3 weeks for the infection to be gone. It probably doesn't hurt to stop after 2 weeks; I mean, what could it do?". People are not even aware of reasoning in such a way and saying "it doesn't have to be well explained" disregards that well known fact about human psychology.
If you want people to do something, explain why. In fact, that even works when your reason doesn't make any sense. "Can I please use the copy machine before you, because I have to make some copies of these documents" will get more compliance than "Can I please use the copy machine before you".
I wouldn't call the average person without the access to knowledge and resources that the average HN user has a terrible person for abusing antibiotics in this fashion but in my opinion, swizec should know better.
The only people who should be selectively following medical advice are people who have made an effort to understand the science behind the advice. The more serious the condition, the better your understanding of the treatment ought to be before you disregard advice.
If a patient has a working understanding of what bacteria are, and how antibiotics work [2], then the patent understands why taking antibiotics for W (where W<X) days might be bad. The reasoning, roughly, is that fewer resistant bacteria will be killed, making you more likely to infect others with resistant strains between when you stop taking it on day W and when you become non-infectious. That sort of patient can do whatever she wants for all I care. She's likely to make a decision that's at least as informed as the doctor's.
That type of patient would never ask why X matters.
[1] Determining X on a per-case basis would involve way too much testing, so the medical community reaches a consensus based on studies (which may or may not be any good), and prescribes drug X for time T based on that consensus. Even if you could afford to get fast test results every few hours to monitor your infection status and see how well the antibiotics were working, and even if you could see what percentage of your infectious colony is resistant, you probably wouldn't want to. Spending that much time in a hospital or clinic is way more risky -- MRSA loves hanging out in those places -- than spending an extra day or three taking antibiotics even if fast accurate tests might show that you don't need to.
[2] It's not binary. It's all about how different concentrations of antibiotics result in different rates of bacterial survival. In any colony of clinically significant size, there are going to be different rates of resistance.