Imagine how that was for people who bought their first coins in 2010/2011. If you told them that Bitcoin would reach $1000 in 3 years, they would probably burst out laughing because it's so hard for people to fathom how something that's worth a few bucks can be worth that much.

I actually had a similar experience with a close internet buddy of mine who is an Ethereum fanboy. He kept repeating that its price would explode well beyond $100 when it was still below $10, which I (with my Bitcoin maximalist cap on) thought wasn't possible because everything at that point for me was a shitcoin and worth zero.

I am sure that he actually believed in Ethereum but was just speculating about its price, but still, he was right and I was wrong. I never ever again will underestimate any coin in terms of price action.