What annoys me with stock is that I'll forever kick myself not putting money on GW as soon as they went public, as I should have known they would have gone up. But now there's the constant worry of if GW's gains are going to just implode with no warning (especially giving dangerous times), so I don't feel comfortable putting money on it even though it just keeps going up.
There's also the classic idea of supporting your own hobbies in multiple ways. Growing up my friend's grandfather owned stock in Pepsi and so their entire extended family only used Pepsi products for everything. Did he own the stock b/c of how much they drank Pepsi? Or the other way around? <shrug>