People and companies, in the United States, and many other common law countries, have certain duties to other people. If McDonald's serves coffee, they have a duty not to serve it so hot and make it so difficult to open that it can spill on you.

That case is just a terrible example of frivolous lawsuits because it had plenty of merit. Actually the vast majority of lawsuits labeled as frivolous, with huge judgement, tend to skim over the details and make it look like the plaintiff hit the lottery with a mild inconvenience: "Oops, she spilled coffee and became a millionaire!"

While our legal system could certainly use a lot of improvements, lawsuits that actually go to trial are being vetted quite a bit.