One of my few complaints regarding Amazon.com is their categorization system (or maybe it's their search function).  I was searching for a dehumidifier and I got several results that were humidifiers.  They're similar machines but they perform the complete opposite function. 

A similar problem is when you can filter search results down to a very specific category, like camera lenses.  When I'm looking in the camera lenses category, I don't want to see cleaning kits and tripods, especially since there's a separate category for camera accessories, and there's even a category specifically for tripods. #technology