Fair enough - if you enjoy doing it, then it's a hobby and it doesn't matter how much you make. But I certainly wouldn't want to put an entire 7+ (or even 6) figure portfolio in a single stock, or even a handful of them. Say that your analysis is dead-on, but some completely unforeseen event strikes the couple of companies you've invested in. There goes a good chunk of your life savings.

I certainly don't think there's a problem with devoting a small percentage of your portfolio (say 5%) to stock picks, or even a larger percentage split over multiple stocks, if you enjoy doing it. I occasionally do it with 5% too. But with retirement savings, I like to have as many guarantees as possible. By investing globally in index funds, I have as much confidence as possible that unless the world implodes, my savings will grow over the coming decades. If I pick individual stocks, even a decent number of them - holding say 10-15 at a time - and even if I actually AM really good at it, it is entirely feasible that I could lose money in the long term through bad luck alone. So even if I can increase my expected value through stock picking, I also significantly increase my risk.

I find personal finance fascinating too, but I prefer to spend my hobby time studying multifactor investing (regression analysis, etc.) and researching the optimal funds to achieve a moderate small and value tilt, while maintaining low costs and broad diversification.