The best way to see how bad the criminal underworld can get is to be part of it yourself - but for most of us, that'll never actually happen.
Still, there are plenty of people out there who've done bad things in the past, but reformed to lead better lives - while warning of the dangers they were previously exposed to.
Take hacking - a few years ago a great video from Vice talked to an ex-hacker, one who'd seen some truly heinous things happen online, but who had turned around to become a better person.
He's what's called a 'white hat hacker', one who works against criminals using a similar skillset, and shows people how to better protect their identities and personal security while they're online.
This is the opposite of a 'black hat' hacker, one who works for their own profit without any morals or hesitations, and this often means criminal activity is on the agenda.
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The white hat that Vice interviewed didn't pull any punches when talking about the scary crimes he'd seen take place, and explained that the goal of many hackers is to hold companies to ransom.
This means seizing either a large amount of sensitive data, or control of their systems entirely, and demanding payment to give them back without making them public, or breaking them.
These ransomware attacks can be devastating, but the hacker also said that he'd seen the amounts of money being demanded go up massively over time: "Back when it started ransomware was charging hundreds of dollars, maybe thousands of dollars for individual targets.
"The bigger payouts that we're talking about now are easily into the tens of millions. This last, most recent attack, they offered $70 million for the campaign key, which is the key that would have unlocked every single computer encrypted during that attack. So we're talking high-stakes games here."
Even scarier than these numbers, though, are the sorts of businesses that hackers are willing to target.
The white hat hacker said he'd seen these ransomware attacks happen to major hospitals - compared to a regular business, in these situations there are lives directly on the line with IT systems that are really important to help doctors treat patients.
Being the person charged with negotiating a way out of that ransom situation would be unbelievably stressful and challenging, and you can understand why the hacker suggested it was the scariest thing he'd seen happen.
It all underlines just how important cybersecurity is in the modern world - when even states and government agencies are getting hacked and held to ransom, it's well worth taking the time to refresh your passwords and stop leaving yourself logged in all over the place, if it could possibly protect you from similar risks.