We live and die one catchphrase at a time. We can't help it. Mantras feel so good as they roll from our tongues. We cling to them because they're catchy, like cotton candy on sticky fingers.

We can be so stupid sometimes.

OK, let me narrow that down. I can be so stupid sometimes. I've been seduced by market poetry. I've accepted a battle cry like "bulls make money, bears make money, but pigs get slaughtered" as a Wall Street truism. But maybe it's time I stick up for this little piggy that went to market.

I understand why bulls make money. There's a historical advantage to being long. Daily downticks and corporate meltdowns show how bears make money, even if it's a trickier practice, given the market's tendency to inch higher over long stretches of time.

But I get lost about this obsession with turning a pig into canned pork product. What's the problem here? Are you a glutton at the feeding trough if you hold onto a company for too long? Of course not. Great investors like Warren Buffett have held winning stocks for generations. Are you piggish because you hold onto a 10-bagger with the hope that it will roll into a 20-bagger? If so, hold your snout up high, because some other Nervous Nellie cashed out earlier when it was just a five-bagger.

I would argue that "bulls make money, bears make money, pigs make more" is a better slogan. Yes, it sounds hedonistically stubborn. There's a certain stench of Gordon Gekko arrogance in claiming that greedy investors come out ahead. However, history teaches us that there are times when it's good to be a pig.

Investors were snapping up shares of Google (NASDAQ:GOOG) when it went public less than three years ago at $85 a share. When the stock opened a few bucks higher, it would have been way too easy to punch out with so many financial analysts tagging Google as overvalued. With every market-thumping quarter, how insane would you be to not take your profits and run? Well, as the stock crossed the $500 mark earlier this year, it produced a sixfold return for its patient investors. Well played, piggies.

When pigs fly
That got me thinking: If that sound bite is flawed, how many other morsels of investing wisdom come with hollow centers? How many people boil down market philosophy to four simple words that can burn them in the end?

Way too many, I'm afraid. My good friend Bill Barker has done a great job of singling out four-word philosophies that work; now I've unearthed my own set of less fortunate maxims. See if any of these have burned you as badly as they have scorched me in the past.  

The P/E is low
Stocks aren't cheap just because the multiples on their trailing earnings are low. Homebuilders have low price-to-earnings (P/E) ratios on a trailing basis but some pretty sobering markups if we look ahead. Utility stocks may trade at low prices, but the same can be said for their growth prospects. A stock with a low P/E is not necessarily cheap.

The P/E is high
Google sported a high P/E ratio through most of its run. Motley Fool Rule Breakers recommendations such as online wedding resource The Knot (NASDAQ:KNOT) and China's leading search engine favorite Baidu.com (NASDAQ:BIDU) always seem to go for market premiums. The key here is that their bottom lines are growing quickly. They have also earned their keep by perpetually trouncing already-lofty expectations. A stock with a high P/E is not necessarily expensive.

Sell on the news
Speculative investors buy on the rumor and sell when they're right, but where's the joy in that? They took on the risk of a certain event taking place, but they're not going to stick around to enjoy the spoils of victory? You saw this happen when Google went public in 2004, with investors fretting over the moment that that the lockup period expired and insiders could begin selling. It failed to happen in a materially damaging way.

You also see this happen every time that Starbucks (NASDAQ:SBUX) seems to find a prolific competitor begin serving premium brews. Whether it's burger-flipping juggernauts or convenience store behemoths, Starbucks seems to do just fine despite the contagious adoption or pricey cups of coffee.

Buy low, sell high
This is probably the most overused tidbit of market jargon. It ignores the obvious: We often don't know what defines too low -- or too high -- until it's too late. Hitting a fresh 52-week low is rarely the sign of a trough. A new 52-week high is unlikely to be a peak. Corporate IP telephony specialist Interactive Intelligence (NASDAQ:ININ) topped the $7 mark two years ago for the first time since the dot-com bubble collapsed. Was the fresh high a peak? Not really. The stock has gone on to nearly triple since then, buoyed by booming business as companies look to shave operating costs by overhauling their communication infrastructure.  

All hogs go to heaven
So where does that leave you? I hope you haven't tethered your life to an arsenal of clever, empty words. Few market truisms are universal. Look around long enough, and you'll find more exceptions to the rule for any prolific claim.

Stocks march to their own beats. Hotels seem like a slow growth business? Try telling that to China's Home Inns & Hotels (NASDAQ:HMIN). The fast-growing operator of bargain-priced lodging is booming in a country that is just starting to discover the joys of travel. Europe's Ryanair (NASDAQ:RYAAY) has seen its shares nearly triple since bottoming out three years ago. The low-cost airline has been generally thriving at the expense of buckling legacy carriers.

I don't follow the guidelines in seeking out my next stock purchase. I know that rules are perpetually broken. I'm smarter than that.

Okay, let me broaden that a bit. We're smarter than that.

Want a four-word phrase that may make you rich, instead? Why not give Motley Fool Rule Breakers a shot? The newsletter picks promising stocks that are reshaping the competitive landscape. The Knot and Baidu.com are active recommendations. And even though "there's no free lunch" is another popular four-word phrase, I'll let you in on a free 30-day pass to eat as much as you like.

This article was originally published on April 10, 2007. It has been updated.

Longtime Fool contributor Rick Munarriz doesn't like to speak in four-word sentences. Well, maybe this time. He does not own shares in any of the companies in this story. Starbucks is a Stock Advisor recommendation. The Fool has a disclosure policy.