Acetaminophen is a perfectly good drug and effective if taken correctly. In high dosages outside of prescribed dosages it will kill your liver and thus yourself on long term use. If one takes a massive dose one time (many grams) it will kill your liver and you will die. It is all that simple.
The real tragedy is Tylenol advertised it products as safe and effective for years and it is. Many young people took overdoses as a plea for attention from family not realizing it was a fatal overdose, as they thought it was safe. It is not safe in high doses. They died a most unpleasant death. Their liver died, they turned yellow of skin and incoherent of logic, with high ammonia blood levels,and died as their blood chemistry would no longer support life.
Every od that comes in the ED has a Tylenol level pulled and gets antidote.