3. Even though we were fishing primarily for fluke, there were plenty of other hungry sea creatures that grabbed the bait. Many of these put up a much better fight than the fluke. I hooked something that seemed very large and heavy, and it put up a nice fight. I was hoping it was a 30-inch fluke, a real doormat, and enough to feed all of us dinner. Unfortunately, it was actually a 2 1/2-foot sand shark. Investment Lesson: If it seems too good to be true, it probably is. Facebook ( FB) seems to be the poster child for many investment lessons these days, and I'll invoke its name one more time here. I was very hopeful that the sand shark on my line was a huge fluke. But it fought much harder than a fluke would have. That did not diminish my false hope, until I could actually see the fish. Facebook came with much promise, but it was overhyped. Some did not want to believe that it simply was not worth $100 billion. 4. Sometimes, after you've waited for a while and it seems as though nothing is happening, it's time to pull up your line. Perhaps your bait has been taken. Or in some cases we experienced Saturday, there was already a small fish on the hook. It was just too small to get noticed. Either way, it's time to begin again. Investment Lesson: Too much patience is not a good thing either. Sometimes you need to close positions, especially if your original reasons for buying are not playing out. I closed my Wendy's ( WEN) position after a few years of waiting for cost cutting to kick in and for a slick advertising campaign and new product offerings to reinvigorate the brand with consumers. It has not played out that way so far, and I've moved on. Those small fish I mentioned, already on your hook despite the fact that you don't notice them, represent an opportunity cost; you can't catch a bigger fish if you've already hooked a smaller one. That's how I came to view Wendy's; owning it became an opportunity cost of owning something better. The good news was that, though there were only two keepers, it was enough fish for dinner. At the time of publication, the author had no positions in any of the stocks mentioned. This article is commentary by an independent contributor, separate from TheStreet's regular news coverage.