Buying coins from exchanges.
Is it a coin if you can buy nearly nothing for it? Is it a coin if you pay fees ridiculously high? Is it a coin when it takes longer to confirm a transaction than to fly around the world?
You buy via an exchange where you first exchange your money for a coin from the exchange to be able to buy a coin of your choice with the exchange coin. The exchange coin shall be always valuable as your own money. Promise!
No proof.
Do not dare to check the management of the exchange.
You made money, congratulations! Unfortunately it is nearly impossible to get your money exchanged back to Fiat money.
Finally, heh, it is a new technology. Fantastic, the new world, everything will change. Have heard that before.
By the way, have you read the paper from Satoshi Nakamoto? You should, read it carefully and then explain to yourself why he hints multiple times to a fundamental flaw in its technology.
After all, humans will be humans.