I depend a lot on product reviews to make my purchasing decisions, both big and small.  I'll read as many reviews as I can before I spend hundreds of dollars on a new gadget, but I'll also look at reviews when only spending a few bucks.  My trick is to look at the negative reviews to see why people didn't like the product.  Usually it's something stupid like they bought the wrong color or there was a problem with shipping.  Rarely is their complaint worthy of a negative review.  But sometimes you can sift through the crap and find some useful information.  And then if you're me, you ignore it. 

That's what I did when I bought a pair of retractable headphones recently.  I kept reading negative reviews and dismissing them because the situation didn't apply to me.  One reviewer said she uses her iPod while running, and the retractable cable wasn't long enough to reach from her hip to her head.  I figured, meh, I'll be sitting at a desk, not running, so that won't matter.  Several other reviews said things about how short the cable was, and I just ignored them because I figured any length of cable would reach from my desktop computer to my ears.  It turned out I was horribly wrong.  I got the headphones in the mail, extended them all the way, and still had to put my head close to my desk to use them.  That's the last time I ignore product reviews.