You'd be forgiven for thinking it's Australian house prices. It's all anyone (including me) has been writing about over the past couple of weeks. Property is out of control, and it's going to bring us down as an economy. Right?

Well, today that's what's on people's minds, sure. But last month? Last month, Donald Trump's nascent administration was going to be the end of us all. He was going to wreck international trade, destroy his country and unleash plagues of locusts while his opponents shouted "let my people go".

Before that? Well, when Hillary Clinton was still the heir-presumptive (feels like a lifetime ago, right?), China was the big worry. We waited with bated breath for the latest acronym soup of data from the government, scarcely believing the actual numbers, but desperately hoping the possibly fictionalised data was at least heading in the right direction (which is as crazy as it sounds).

Consumer spending, producer prices, steel stockpiles ??? the markets were fixated with each one and a dozen besides. The smartest people in finance were waxing lyrical on whether the Chinese landing would be "hard" or "soft", and what we could and should do in response.

F. Scott Fitzgerald suggested "the test of a first-rate intelligence is the ability to hold two opposed ideas in mind at the same time and still retain the ability to function". In the market, simply holding two ideas - any ideas - at the same time seems taboo.

Instead, we careen from one impending disaster to the next, as the mood takes us. No wonder those selling doom and gloom do a roaring trade.

Now, some of you reading this will be thinking "Not me, I think they're all problems, and things are getting worse. I worried about China, then Trump, then housing and the trifecta just magnifies the issues". If so, I don't know how you sleep.

Because before that, there was Brexit. Before that, the prospect of rising US rates. Grexit. Cypriot banks. The PIIGS economies. The US fiscal cliff (remember that?). The prospect of a double-dip US recession in the immediate aftermath of the global financial crisis.

If you're a worrier, at least one thing you don't have to worry about is whether or not there will be new potential crises to fret over.

There has been no shortage of fears over the past decade. Ironically, those who remember the GFC have learned the completely wrong lesson. The message that we all should have taken from the GFC isn't that crises are just around the corner.

Instead, we should have realised that the first real economic setback since the early 1990s was the exception, rather than the rule. That these things, painful though they are, happen very rarely. That there were a few dozen other reasons to worry - before and since - that simply never materialised, or did, but had little to no impact on the economy or the market.

Foolish takeaway

It's entirely possible that housing is the catalyst for the next recession. Or Donald Trump. Or China. And we're wired to worry. Smart people, people I respect, have been fearing a China collapse for over half a decade, in which time, the ASX has gained more than 70 per cent, and that includes the mining bust (which incidentally was more about supply than Chinese demand). It doesn't mean the risk wasn't - isn't - real. It just means invest anyway. In the long term, not investing is the biggest risk of all.

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Scott Phillips is the Motley Fool's director of research. You can follow Scott on Twitter @TMFScottP. The Motley Fool's purpose is to educate, amuse and enrich investors.