For noobs, HODLing is a term used for "holding" your assets (here: Bitcoins) for a very long time. But, isn't it true that those who bought it at $500 once should have sold it at $20k peak, and if not, why didn't they sell at $15k?
We have our own targets on taking profits. I'm sure most people sold some at $15k to take profit and re entry when bitcoin dipped below $15k. For me my goal for next selling is the new ATH @ around $22k is the spot that I'll be selling my bitcoins now.
Isn't it true that too long a hodl can stop you from taking great opportunities while sitting dumb and waiting for a specific target?
It is true, that's why you should always split funds between hodling, trading, buybacks or any good opportunities in some altcoins circulating now. Opportunities are passing by everyday if you go all in on hodling, just like @Lorokan said too much of everything is bad.