That's what happens when you don't trust and don't keep patience in the reality. Since I started I have always been know to bitcoin being expensive grower in the market and the market cap will always grow more like this now and forever. I will always withdraw money if I want to but I won't go for emotional selling of the bitcoins in first place. Anyway you can always grab this chance the only thing is you will have to buy the bitcoin at very high rates now and then your ROI will come at very expensive prices. This will keep happening always no matter what. Bitcoin still not reached Pluto though, when it will be there then you can expect to have 10K USD per btc.
It's reasonable for most people to become skeptical of it and sell. In the beginning of this year BTC was around $800 and I remember when people were freaking out about a bear run when it was 1k. Makes you wonder where the ceiling is and the possibilities of this in the future. Maybe 10k BTC will be something we may regret to sell as well - maybe not.