To be fair, as the euro zone crisis deepens and economic data around the world disappoints, U.S. companies are finding it harder to grow revenue now than at just about any time since the financial crisis. Expectations for U.S. company earnings are on a slippery slope down Wall Street.

However, these negative messages should be taken with a grain of salt.

While the downward slide in estimates highlights the caution analysts and companies are expressing, investors should also be aware that companies are setting lower goals so that they can look better or be able to beat estimates when the results come out.

Bed Bath & Beyond Inc. (Nasdaq: BBBY), The Procter & Gamble Company (NYSE: PG) and Adobe Systems Incorporated (Nasdaq: ADBE) are the latest companies to trim earnings forecast for coming quarters.

Second-quarter earnings growth for companies in the S&P 500 index is expected to be only 6.5 percent, down from an early January forecast of 10.1 percent, according to Thomson Reuters data. Excluding profits-generating machine Apple Inc. (Nasdaq: AAPL), analysts on Wall Street are looking for earnings growth of 5.8 percent in the second quarter.

S&P 500 second-quarter revenue projections now stand at 2.2 percent, compared with an average 7.3 percent quarterly increase since the fourth quarter of 1998.

U.S. corporations' outlook for subsequent quarters has also deflated. Revenue growth forecast for the S&P 500 is for 2.9 percent in the third quarter and 4.1 percent in the fourth quarter.

A roundup of some recent guidance cuts:

Bed Bath & Beyond Inc. (Nasdaq: BBBY), the home-goods chain, issued a weak second-quarter profit forecast on Wednesday after market closed. The Union, N.J.-based company pegged earnings per share between 97 cents and $1.03, compared with the Street consensus of $1.08 a share. Earnings for the fiscal 2012 would rise between a high-single digit and low-double digit percentage rate.

The Procter & Gamble Company (NYSE: PG), the world's largest household product maker, lowered its fourth-quarter earnings and revenue forecasts Wednesday, citing unfavorable foreign exchange rates and slower growth in China and tough markets in Europe and the U.S. The guidance cut, announced during a presentation at a Deutsche Bank Global Consumer conference in Paris, is the second time in three months that P&G has lowered its outlook.

Chief Executive Officer Bob McDonald reaffirmed P&G's restructuring plan, which involves cutting 5,700 jobs by the end of fiscal 2013 and saving $10 billion by the end of the fiscal 2016.

The maker of Tide detergent and Pantene shampoo said it expects adjusted fourth-quarter earnings between 75 cents and 79 cents per share, down from its previous estimate of 79 cents to 85 cents per share.

Revenue is anticipated to drop one percent to 2 percent compared with a prior outlook for a one percent to 2 percent increase.

Adobe Systems Incorporated (Nasdaq: ADBE), maker of Photoshop and Acrobat software, lowered its full-year revenue outlook as weak demand in Europe could hurt sales of the recently launched Creative Suite 6. In normal times, Adobe's sales would surge after a Creative Suite upgrade.

Adobe now expects revenue growth of 6 percent to 7 percent, implying full-year revenue of $4.47 billion to 4.51 billion and an adjusted profit of $2.40 to $2.46 per share. It earlier forecast a profit of $2.38 to $2.48 per share, excluding items, and revenue growth of 6 percent to 8 percent.

FedEx Corporation (NYSE: FDX), operator of the world's largest cargo airline, said Tuesday that slow economic growth would crimp its earnings over the next 12 months. The Memphis, Tenn.-based company predicts fiscal 2013 earnings of $6.90 to $7.40 a share. That excludes the major cost reductions it plans to announce in the fall.

Starbucks Corporation (Nasdaq: SBUX), the world's largest coffee-shop operator, trimmed its earnings forecast for the year by about 2 cents a share on June 12.

We continue to struggle, as many have, with the macro challenges that we face in Europe. Those challenging trends have continued for us even more than we had expected as we are in this third quarter, said Chief Financial Officer Troy Alstead.

Starbucks now expects the high end of its fiscal third- and fourth- quarter earnings to be 45 cents and 47 cents a share, respectively, lowering each by one cent.

McDonald's Corporation (NYSE: MCD), the world's largest restaurant chain, cut its earnings forecast for the second quarter on June 8 by 7 cents to 9 cents per share.

Tiffany & Co. (NYSE: TIF), a bellwether of luxury spending, said on May 24 that its global sales aren't rising as fast as in 2011. The jewelry chain lowered its earnings outlook to $3.70 to $3.80 a share for the year, compared with an earlier forecast of $3.95 to $4.05 per share.

Tiffany also trimmed its sales estimate, calling for a rise of 7 percent to 8 percent, instead of the 10 percent originally projected.

Kellogg Company (NYSE: K), the largest U.S. maker of breakfast cereal, reduced its full-year earnings forecast on April 23. Earnings per share will be $3.18 to $3.30, instead of the previously predicted $3.25 to $3.37 a share.

We are obviously disappointed with the performance of the company, Chief Executive Officer John Bryant said in the statement.