Actually, it was not that unreasonable, despite how it gets framed. This case is often presented as "middle age lady buys coffee at McD's drive through, puts between legs and gets burned as she drives off." If you look into the facts the truth is quite different.
1. McD's knew temperatures were unsafe but they decided to continue to serve it at temperatures that were unsafe to drink. McD's already had over 700 reported cases of burns from their coffee
2. Despite what people often say, she was not driving, but a passenger in a stopped vehicle when she got burned.
3. Her original request was for McD's to cover her hospital costs, when they said no she sued.
There are many frivolous lawsuits, but in this case McD's acted with callous disregard for the safety of its customers by knowingly serving coffee at temperatures that were unfit to drink and dangerous.
The suit against Apple, however was frivolous.