Paracetamol is probably the most dangerous over the counter drug on the market and the window between the effective treatment dose and the overdose and the lethal dose is incredibly narrow, with a lethal dose being as few as 15 tablets, depending on body weight. Which isn't much considering a normal daily dose is 8 tablets.
Added to that, with paracetamol you can get what we call a staggered overdose, where you are taking too much, but spread out over a period of time (i.e. for pain), and those patients are harder to treat and have a worse outcome than patients who decide to 'end it all' and swallow a handful of pills in a fit of pique, because with the single overdose, the treatment is targeting one block of drug. Staggered overdose hits time after time.
Some people are lucky and survive long enough that we can get them to a regional hospital for a liver transplant. Some aren't, and it's a really painful way to die.
I'm really paranoid about paracetamol. I give all sorts of drugs at the hospital, but it's paracetamol that I double and triple check the system before I give, and check the time last given. At home, I say clearly to my DH, 'so that is paracetamol, given to DDX, at 14.45'. The children's school has a policy that they can give paracetamol, so I only ever give them ibuprofen if they need pain relief before school, to guarantee that they can't be double dosed. That's how seriously, as a nurse, I take paracetamol.