John Stossel: First, the bad news
But that leaves plenty of room to take things wildly out of context.
That's where most big scare stories come from, like recent headlines about GM foods. GM means "genetically modified," which means scientists add genes, altering the plant's DNA, in this case to make the crop resistant to pests.
Last week, Poland joined seven other European countries in banning cultivation of GM foods.
The politicians acted because headlines screamed about how GM foods caused huge tumors in rats. The pictures of the rats are scary. Some have tumors the size of tennis balls.
What the headlines don't tell you, though, is that the female Sprague-Dawley rats used in the test usually develop tumors - 87 to 96 percent of the time.
It's a similar story with chemicals that the media constantly tell us to fear.
More often than not, rats get tumors if given high enough doses of manmade chemicals. I shouldn't say "manmade." Nature's chemicals cause tumors at the same rate.
Reporters and environmental activists have incentives to leave out details that might make the story boring. It's useful if you think you're in danger.
"It's a great way to get attention," says Bjorn Lomborg, statistician and author of "The Skeptical Environmentalist," "but it focuses you on the wrong solutions." Instead of doing something that really fights cancer, like quitting smoking, people devote their energy to banning things like GM foods.
GM foods require less water, need fewer pesticides and grow where other crops will not survive.
By forcing farmers to stick to the old-fashioned corn, activists and regulators force customers to pay higher prices for food.
Reporters sleep with clear consciences because we (usually) don't say anything completely false. We tell ourselves that we may save lives and draw attention to important issues - and so what if people err on the side of safety?
But the answer to "so what?" is that people waste time, money and emotional energy, and we are less safe, because we worry about the wrong things.
Years ago, the Natural Resources Defense Council claimed the chemical Alar, which helps keep apples from rotting, killed kids. When "60 Minutes" ran the story, I believed it. So did lots of people.
Schools across America banned apples. Moms poured out apple juice. Apple growers lost billions.
But the scare was bunk. Apples, even apples with Alar, are good for you. Since banning Alar meant apples decay more quickly, apples become slightly more expensive, and that meant some kids ate less healthy food.
Today, we have new scares, like the one over plastic water bottles. Some contain a chemical called BPA, which activists say causes cancer, hyperactivity, all sorts of problems.
Chemicals called phthalates, which keep school supplies like backpacks soft, are accused of damaging kids' livers and kidneys and causing asthma.
If these stories were true, who could blame parents for being frightened? Who can blame reporters for telling the story?
Julie Gunlock, from the Independent Women's Forum, blames them. She points out that the activists scare mothers needlessly, because "over 1,000 studies, independent studies, have said that BPA is perfectly safe."
She knows how the scare stories work: "BPA is easily vilified. I mean, it's invisible. And people tend to say: 'Chemicals, it's scary. I'll just trust what some activist organization or consumer rights organization says and avoid it.'"
There's no reason to get excited about chemicals - unless you're an environmental activist eager to acquire money and power.
"A lot of them make money on newsletters," says Gunlock. "Bad news sells." NRDC has raised $185 million by scaring people.
To keep scares in perspective, remember all the good news that gets less attention. Coverage of horrors like the shooting in Newtown, Conn., makes us think our kids are in more danger today, but school violence is actually down.
And despite all the chemicals - actually, because of them - we live longer than ever.
There is plenty of bad news that's real - like the national debt, and most of what politicians do. But in most ways, most of the time, the world slowly but surely gets better. To most of us, that's good news.
John Stossel is host of "Stossel" on the Fox Business Network. He's the author of "No They Can't: Why Government Fails, but Individuals Succeed."