They always feel like they have come out of the blue. Even if — as was the case with last week's turmoil — every man and his dog has predicted we're due for a fall.
It's not rocket science. For almost nine years equity markets have benefited from the low interest rates put in place to save the world from the last financial crisis.
Finally, as the US economy starts to see good growth, the rates are being lifted back to normal settings.
As rates rise cash investments like bank deposits and bonds look more appealing.
So naturally some investors exit the stockmarket for less risky options.
Higher interest rates will also raise costs and dampen profits for shares in businesses that carry a lot of debt.
Everyone can see markets are extremely highly valued and prices are due to correct.
As the whole process has been slow and well-flagged by the US Federal Reserve you'd think it would be orderly.
But markets just never seem to act in an orderly way. I blame people.
Let's face it humans are famously prone to excesses of fear and greed.
When markets fall sharply the first question financial journalists always get is: should we be panicking yet?
The answer is always: no.
You should never panic, even if your house is on fire. Even if there's a zombie apocalypse.
Panicking doesn't help. Rick Grimes didn't stay alive for eight series of The Walking Dead by panicking every time the zombies broke through the perimeter fence.
To be fair, what most people really want to know is how bad things are in historic context.
That isn't necessarily obvious when turbulence hits. Markets don't always crash in one day as they did in 1987 and 1929.
There was a morning in 2008 when Lehman Brothers collapsed and it felt like the global economy was really going to seize up.
But the global financial crisis was well advanced by then and had unfolded with a series of market falls across months.
So we don't know how this cycle will play out.
Fundamentally, it's an improving global economy driving the turmoil so a recession caused by a share crash makes no sense.
If market falls are bad enough to damage economic growth we should see central banks back away from rate rises.
That happened in 2015 and 2016 — markets effectively spat the dummy.
This time there's a belief that the US Federal Reserve has the bit between its teeth.
Hmm, we'll see.
The other question we get asked is: How will this affect me?
Are you highly leveraged trader? No?
Good, so there's probably not too much to sweat about for now.
It is possible your KiwiSaver balance will fall. But the odds are you're in one of two kinds of KiwiSaver funds.
If you take an active interest in your savings and have a more aggressive fund you should know you have just benefited from one of the biggest equity booms in recent history. You should stay focused on long-term growth and short-term falls shouldn't bother you.
Or you might be the kind who doesn't pay much attention and is still stuck in a conservative KiwiSaver default fund. That means a larger chunk of your money is already in cash investments.
You won't be hit hard by a crash.
You should have been worrying about the boom. You've missed out on thousands of dollars of returns.
Ultimately, there is a possibility a crash could reveal some previously unknown weakness in the financial system, which spills into the real world.
In the GFC the trading of home mortgage debt as financial products was exposed as woefully risky.
Billionaire investor Warren Buffet once said — "Only when the tide goes out do you discover who has been swimming naked." Here's hoping we're all a bit smarter this time around.
I wouldn't count on it, but neither do I see a change market conditions as inherently bad.
There are aspects of the New Zealand economy worth worrying about — our overvalued, highly leveraged property market remains top of the list.
If interest rates were to soar, we'd have serious problems.
But the rest of the economy is in pretty good shape.
Most of us are at least one step removed from the reality of equity market crashes.
That makes it a little bit easier to sit back and enjoy the drama.
