We live and die one catch phrase 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 the battle cry "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 going 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 over this obsession with turning a pig into a canned pork product. What's the problem here? Are you a glutton at the feeding trough if you hold on to a company for too long? Of course not. Great investors, including Warren Buffett, have held winning stocks for generations. Are you piggish because you hold 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 grabbing shares of Research In Motion for a fifth of today's split-adjusted price three years ago. The stock wasn't cheap back then, either. The company's signature BlackBerry wasn't even new. It has been on the market since 1999.

However, whether the market figured that Palm (NASDAQ:PALM) would come up with a better mousetrap or that Nokia (NYSE:NOK) wouldn't take the PDA revolution lying down, the market's apprehension fed Research In Motion just fine. 

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, say, 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 whether 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"
Research In Motion sported a high P/E ratio through most of its run. Motley Fool Rule Breakers recommendations such as solar-cell maker Suntech Power (NYSE:STP) and nanotech-device specialist FEI (NASDAQ:FEIC) always seem to go for market premiums. The key here is that they are both growing quickly.

Stay ahead of the pack, and the numbers in the rear view can appear deceiving. 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 that a certain event would take 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 the lockup period expired and insiders could begin selling. What was anticipated failed to happen in a materially damaging way.

You also see this happen every time Amazon.com (NASDAQ:AMZN) seems to bump up against a threat such as encountering a traditional retailer that's ramping up its online presence or a niche online retailer that's beginning to diversify. Through it all, Amazon seems to do just fine despite the revolving door of wannabe combatants.

"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, and a new 52-week high is unlikely to be a peak. You see the truth of that statement all of the time, with companies such as Research In Motion, Google, and Amazon. Fresh highs aren't permanent peaks. If anything, a year later, they often start being referred to as a 52-week low.

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. No one is going out to eat anymore? Tell that to Kona Grill (NASDAQ:KONA). The casual-dining chain is on a roll. Expansion fueled a 63% top line surge this past quarter, with a sharp 5% gain in comps bucking the industry's sluggish trend.

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.

OK, 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. FEI and Suntech Power 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. Palm and Amazon.com are Stock Advisor picks. The Fool has a disclosure policy.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.