To be more serious:
Clearly, a 6 HP 1st-level Wizard can only take 6HP of damage before dying. But that doesn't mean that they have less health or are more easily killed by a short sword than something with higher HP. It means that their luck, their constitution, their physical training, their heroic abilities, they're not high enough to take that much damage. But it's not like 6 papercuts in a row are going to kill that Wizard. None of those paper cuts would deal meaningful damage. There's no point to assign HP damage to something unless the risk of death or serious injury is significant or severe.
This is why JRPGs treat HP in much more granular gradations than D&D does. At that small a level where an attack from a mid-level character in a game may do hundreds of damage points, you can afford minor inconvenience damage such as from paper clips to deal just a couple of points. But at that point the abstraction becomes very confusing. Am I a sack of meat than can be cut X number of times before I fall to the ground bleeding out? In actual combat, most attacks would be parried or avoided or missed, because if they actually hit I'd be dead. So to some extent, HP is health, but a lot more of it is luck and measure of vitality or energy (an ability to avoid and shave off injury or to push through it and suck it up), and eventually we get tired enough that we can no longer do that and an attack hits hard enough that we start bleeding out.
That's why 4e introduced the term Bloodied as a measure of when an attack first deals substantial damage to your body, and it's at about half your total HP. At that point, it's time to take a break and heal up and try to catch your second wind.
Not trying to argue, but yes, these are the fundamental questions being asked by the OP.
