There is a lot more luck involved in stock picking than other skills such as computer programming or basketball, and investors tend to start identifying with their investments if they deviate from the default choice - they become the person responsible if it goes down, but the genius if it goes up.
The speaker discusses managing wealth and the risks involved in investing in individual stocks.
The term "don't buy the dip" is often misunderstood to mean that one shouldn't buy a stock during a price dip. However, the phrase actually refers to avoiding the practice of holding cash and waiting for a dip, as this often causes investors to miss out on potential gains.