There are many things most likely to consider whenever you're investing money in crypto..
These are:
1. Volatility of the Market.
2. They don't have the knowledge about crypto.
3. Negative news that they see or hear in social media/TV Media.
4. They were scammed and afraid to invest again.
5. Threats of hackers in the internet.
But users can also protect their computer from hackers by using:
1. Virtual Private Network for Internet Protocol
2. MetaMask Wallet
3. Not saving any private keys in your PC.
And also, there are many FUD's from the famous bitcoin investors are spreading including the FUD from Faketoshi which is believed by many, and I think it is not a thing to worry about. In order to be successful here in crypto is to become a responsible crypto user.