What’s the one Web3 hack you’ve taught a friend, and why’d it blow their mind?

my friend was fairly new to Web3, dabbling in crypto by holding some Ethereum and a few ERC-20 tokens on a centralized exchange like Coinbase. They’d heard horror stories about exchange hacks—think Mt. Gox or the more recent FTX collapse—and were vaguely aware of the mantra “not your keys, not your crypto.” But they didn’t really grasp what that meant until I walked them through the process of taking true ownership of their assets. I suggested they get a hardware wallet, which is essentially a small, tamper-proof device that stores your private keys offline, away from the prying eyes of hackers or the risks of internet-connected software wallets.