Yup, just your own private mini-index fund. I had a couple of great uncles that did the same.
My biggest mistake was thinking that they were fuddy-duddy and old fashioned and that now a days, we have better more high tech and totally genius ways of picking stocks and timing the market. Still fool's errands.
I will say that modern portfolio theory is, IMO, a sound way to distribute funds in asset classes. That, and your stomach for risk.
Just a little story that my dad put me onto. When a broker calls and has a hot deal, it means that his firm is getting a big bonus for pushing some cash strapped company. Hot undervalued items do not exist. The market adjusts value in a matter of seconds.