Problems

• Stressful to send funds between wallets. One typo could result in total loss of your funds!
• Lack of ease-of-use if you're not well versed with technology.
• High gas fees, the more people use or transfer a coin the higher the cost will be!
• Mass adoption takes time delaying crypto moons.
• Massive amount of shit, meme & rugpull coins.
• The enviromental impact of mining.
• Govenment regulation is coming.
• Problem with inhertiance.

Worries

• Lack of understanding from the general public.
• The market is volatile and easily swayed by news, media & celebrities.
• Shaky market and situation regarding the regulations at the moment.
• Not all cryptos solve real problems.
• Adoption.

Something that Crypto does however is fight inflation & give power to the people instead of to the banks.

I am not saying that you should always worry about these problems or take them to heart. But it's important to keep the flaws of a system in mind before you invest.