This vid is very pertinent to me. Very often I get "married" to some of my investments/positions and it gets very psychological when it comes time to take profits. Investor psychology is a funny thing.
EDIT: As for the recent drop-off, I think it has to do with the market anticipating a bear market due to the Segwit2X shitstorm in November.
Agreed, never get married to any of your investments, whether it's big profits or big losses!
great advice, but it can be very difficult sometimes :-(