If I didn't know any better, I'd say that if the broad-based S&P 500 (SNPINDEX:^GSPC) could be personified, it'd certainly be a hypochondriac. Day in and day out, persistent worries regarding the imminent tax hikes and spending cuts -- known as the fiscal cliff -- that are set to take effect on Jan. 1, are sending investors scurrying for the hills. Today marked the third straight day of losses for the S&P 500, which is now down 7.5% over the past four weeks. The index finished today down 2.17 points (-0.16%), to 1353.32.

As my Foolish colleague Dan Carroll pointed out earlier today, disappointing earnings results from retail giant Wal-Mart (NYSE:WMT) helped push an already fragile market lower. For the quarter, Wal-Mart recorded $113.2 billion in revenue on a 1.5% rise in same-store sales. Wall Street had been expecting the cost-conscious retailer to report $114.96 billion in sales and a 1.8% rise in same-store sales. Contrary to popular belief, high unemployment levels and tighter consumer spending domestically, and lower consumer traffic in China, are wreaking havoc even on the world's biggest retailer. Shares shed 4% today to finish at its lowest levels since June.

Payment services and lending provider Discover Financial Services (NYSE:DFS) is also having a particularly rough day, down 4%, after October's data showed that delinquency rates at the company rose by two basis points, to 1.84%. What investors need to keep in mind is that Discover's delinquency rate is historically low by all measures, and I wouldn't allow today's slight uptick to scare you away from what has been a truly consistent performer.

Looking on the bright side, NetApp (NASDAQ:NTAP), a provider of network storage solutions, roared past the Street's second-quarter EPS projections by $0.03, noting that gross margin expanded and its European business demonstrated accelerating growth. NetApp's predominantly in-line forecast speaks to its steady growth, and earned it an upgrade to "outperform" from Raymond James Financial. I can't say I'm as sold on NetApp as Raymond James is, considering its European exposure, but shares nonetheless advanced 11% on the news.

Lastly, office supply superstore Staples (NASDAQ:SPLS) proved that profits can come easy. On top of yesterday's rally following a better-than-expected third-quarter earnings report, Staples tacked on an additional 3% today. Staples commented yesterday that it expects EPS growth in the low single-digits this year, as opposed to the consensus estimate, which called for a slight drop in EPS. Credit Staples' downsizing efforts and fresh product mix for that recent bottom-line boost.

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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.