Not to stand up for lawyers or anything but the McDonald's suit that everyone used to point out stupidity was valid. That cup of coffee caused THIRD DEGREE BURNS because McDonald's required franchisees to serve coffee at 180–190 °F (82–88 °C). No one expects that a beverage would be served at such a high temprature. The resulting 3rd degree burns (mostly on her labia and clitoris and anus) resulted in 8 days of hospitalization for skin grafts and two more years of medical treatment.
But here is what really sank the clown's food joint:
Other documents obtained from McDonald's showed that from 1982 to 1992 the company had received more than 700 reports of people burned by McDonald's coffee to varying degrees of severity, and had settled claims arising from scalding injuries for more than $500,000. McDonald's quality control manager, Christopher Appleton, testified that this number of injuries was insufficient to cause the company to evaluate its practices.
That is what made it negligence, because they could not argue that it was unforeseen, indeed, it makes them responsible, because they did know.