1. Lethargy during a sideways market
2. Disregarding your strategy
3. Chasing somebody elses dream
4. Believing somebody elses FUD
5. Using money that you shouldnt be
6. Failing to properly do a self risk analysis before investing
If you can cope with these dangers then this type of investment will do well for you. This is a hands-off, long term method of investing. DYOR, find good coins with bright futures, buy and hold. Dont worry about the daily percentages
All of them are dangers that anyone can face in Hodling cryptocurrency but I believe that the number 2,5 & 6 are the main problems here. One should never disregard their own strategy, whatever strategy you have decided to use at the beginning and you believed it was going to work for you, then you should stick to that and disregard it because of what others are saying.
And never use any money that youre not meant to use in trading cryptocurrency cause you might lose it, just use what you can afford to risk. Lastly, doing self analysis is what anyone shouldnt fail to do, cause most of the times its not good to rely on other peoples analysis, majority of them are always wrong.