It's like clockwork. You can almost set your watch by it: Big pharma announces an acquisition of a little biotech for a substantial premium and moments later someone complains on the message board.

That's right, complains ... about the value of their portfolio going up! Some of the reasons are somewhat understandable, but others, most even, are just nonsense.

So much potential
This seems to be the most common complaint. Investors buy into a biotech company hoping for a 10-bagger after a drug is approved. Instead, they end up getting capped at a double when the biotech gets acquired.

I see the argument. If Dendreon's (NASDAQ:DNDN) board had sold at $6 when the stock was trading near $3 earlier this year, investors would have been outraged; after all, the stock is trading near $25 now.

But no one knew for certain that its prostate cancer treatment Provenge would pass its phase 3 trial. In fact, a lot of people thought it wouldn't work -- that's why it was trading so low. Getting double what most investors felt the stock was worth the day before shouldn't be discounted, even if it is disappointing.

All that work for naught
This one actually makes a little sense. You spent a long time figuring out that Medarex's (NASDAQ:MEDX) ipilimumab is a potential wonder-drug, and doubling your money doesn't justify the time involved in researching the company. You could use the proceeds from the buyout and invest in Bristol-Myers Squibb (NYSE:BMY), soon to be ipilimumab's new owner, but even if the drug is a blockbuster, it's not going to move Bristol-Myers' $20 billion revenue needle all that much.

The simple solution is to remember that investing is supposed to be fun. The thrill of the hunt should excite you. If it doesn't, consider sticking your money in an ETF or index fund and enjoy doing something else. I hear gardening is nice this time of year.

Whether you like potential one-drug wonders or companies like Exelixis (NASDAQ:EXEL) and Seattle Genetics (NASDAQ:SGEN), which both have multiple shots on goal, there's plenty of fish in the investing sea; get out your pole and start researching again.

Benefits management the most
It's often true that the value of automatically vesting stock options trumps the equity of individual investors. But you kind of knew that going in didn't you? Management has to be rewarded somehow for their work. Assuming the price is right, it’s a win-win -- even if management's win is bigger.

Selling for a loss
It can be disappointing for long-term shareholders to see their company taken out for a premium that's below the original purchase price. Johnson & Johnson (NYSE:JNJ) took out Mentor for a 92% premium, but it was still less than the stock was trading for a year before.

It happened to the Motley Fool's Rule Breakers newsletter as well; Gilead Sciences (NASDAQ:GILD) picked up CV Therapeutics for $20 a share, which was still below the price it was recommended at three years ago -- remember the bull times of 2005?

But remember, except for tax planning, you should avoid making decisions based on your cost basis. When deciding whether to sell or hold, the question should be whether the stock has potential to increase in value. Your original purchase price is fairly irrelevant, as circumstances were different back then.

Still haven't convinced you to stop whining?
Go buy some Johnson & Johnson. The company has survived over 100 years without being taken out. Short of Buffett, Icahn, and Gates getting together to buy this American icon, I think you'll be safe from a takeover.

Exelixis is a Motley Fool Rule Breakers pick. The newsletter is always on the hunt for hot drug stocks and other cutting-edge picks. Click here to see all of our latest discoveries with a free 30-day trial subscription.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. Johnson & Johnson is an Income Investor pick. The Fool owns shares of Exelixis. The Fool has a disclosure policy.