And one of my favorites tells us that "Bulls make money, bears make money - and pigs get slaughtered."
With apologies to Gordon Gekko, while greed may be good, excessive greed can be hazardous to your health - and to your portfolio.
And a news item I spotted last week drove that point home.
Last Monday, the trade journal Canadian Business reported that Canada has issued a "thumbs-down" verdict on a deal that calls for Malaysian state-run energy giant Petronas to pay $6 billion for Progress Energy Resources Corp. (PINK: PRQNF), a natural-gas producer that's based in Calgary.
Canadian Industry Minister Christian Paradis said Ottawa nixed the deal because the administration of Prime Minister Stephen Harper was "not satisfied that the proposed settlement is likely to be of net benefit to Canada," Canadian Business said.
Needless to say, the free-market crowd is using the Harper Administration for target practice - alleging the rejection will have a chilling effect on all foreign investment north of the border.
Greed is Not Always GoodOf course, that's a political concern. My focus today is on the investing fallout ... and the lesson we can learn from it.
As a result of the decision, the value of other resource companies - especially ones investors thought might serve as decent takeover candidates (at a nice premium) - have also been hit.
Investors are also worried the decision also puts at risk the proposal by China's CNOOC Ltd. (NYSE ADR: CEO) to buy Canadian oil-sands player Nexen Inc. (NYSE: NXY).
And that brings me back to my "pigs get slaughtered" point.
You see, Permanent Wealth Investor Editor Martin Hutchinson twice recommended Nexen shares to Private Briefing subscribers - first in early September 2011 and then again in early July of this year ... just two weeks before CNOOC offered to buy Nexen for $15.1 billion, or $27.50 a share.
Afterwards, the stock jumped to $26 - 33% and 54% above where he'd recommended it to you, but a full 6% below the "offer" price of $27.50.
When the Nexen deal was announced, a lot of folks asked us whether they should cash out and take their winnings, or hold out for that last 6% - which, admittedly, is a significant amount of money in today's zero-interest-rate world.
Martin didn't hesitate. In fact, he gave readers the same advice he gave his own subscribers (who, by the way, pocketed 68% on the deal).