Happiest moment for all of us: Bitcoin reaches its peak at almost $20K, Everyone has very happy around the last quarter of 2017 because everything is going our way. Lots of people making tons of money out of crypto.

Saddest moments: When we hear a exchange being hacked, government banning, regulations.

Personally, saddest moment for me is when I lost my private key for a chunk of my bitcoin way back 2011-2012. It's around 10 BTC so its really hard for me to take that lost. However, I already move on and almost got back on track to hit that number again.