I believe the Charlie Munger one said that Berkshire Hathaway was really nothing more than 40 decisions made over a period of 40 years. I have long been a believer that less is better. For me, this means less trading and fewer positions over long periods of time.
Index investing also allows me to avoid investing in individual positions where I would have to answer the following question: if I could afford it, would I want to own the entire company? Over the years, I found a handful of companies that I would want to own in their entirety, and so I purchased shares with a view of holding them forever: Berkshire, Markel, Apple, Merck and more recently Shopify (which I purchased well before it’s ridiculous run).
I like index investing, and I like purchasing individual positions, but I do both with a very, very long-term view. I’m not recommending it for everybody but it’s worked for me.