Let me guess: your friend has only been investing for the past 10 to 12 years. The past 10 years were very good times. Yes, there were a couple rough patches (March 2020, anyone?), and years where things went nowhere (2014-2016?) but if you stayed the course, you were more than fine. If you literally did nothing except put your money in an S&P fund, reinvested all dividends, and waited, you'd be up 15% annually. It won't be like this forever...