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 on to 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 on to 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 5-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 Hansen Natural (NASDAQ:HANS) four years ago for less than $4 a share. A pair of subsequent stock splits lowered that price to an adjusted basis of less than $0.50 a pop. Those who didn't want to be greedy may have cashed out two years later, when the stock was a 10-bagger. Those still holding onto the maker of Monster energy drinks are now sitting on a 70-bagger.

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 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
Hansen sported a high P/E ratio through most of its run. Motley Fool Rule Breakers recommendations like financial rates authority Bankrate (NASDAQ:RATE) and athletic apparel maker Under Armour (NYSE:UA) always seem to go for market premiums. The key here is that they are growing the bottom line quickly. 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 Marvel Entertainment (NYSE:MVL) had a hit with Spider-Man in the summer of 2002. The shares took a hit as buyers bailed, even after the movie established itself as the multiplex magnet of the season. Those who stuck around had their Spidey sense in the right place. The stock has soared roughly 700% since then.  

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. Alternative beverage specialist Jones Soda (NASDAQ:JSDA) was trading in the single digits until it finally poked its head above the $10 last summer. Too high? A sweet canned-soda distribution deal now finds the new pop star fizzing along in the high teens.  

All hogs go to heaven
So where does that leave you? Hopefully, 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. Move (NASDAQ:MOVE) has been able to grow in a moribund real estate market by shedding its Homestore.com skin and broadening its homeowner-related offerings. BJ's Restaurants (NASDAQ:BJRI) has seen its comps climb higher for 41 consecutive quarters, despite the ups and downs of its more fickle casual-dining peers.  

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. Bankrate and Under Armour 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.

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. He is part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. Marvel is a Motley Fool Stock Advisor pick. The Fool has a disclosure policy.