They should make a sticky called "Why Do My Pictures Suck?".
The format would be: someone asks "Why do my pictures suck?" then (required) posts an example, both at "regular" size (shrunk for the Web) then a 100% crop from the offending picture. Exif is also required, and any pertinent details of technique (ideally it would be something like "I shot this on a tripod with a cable release and Mirror Lockup with no wind, so I am quite sure it wasn't camera shake"). Short and concise, then followed by short and concise answers (unhelpful ones removed by the moderator) that together could comprise both a must-read and a "living encyclopedia" about why some pictures suck and what you can do about it.
Several factors make a difference between "My picture sucks" and "Hey, I actually captured a great image!". We've all had "sucky" pictures, but progress in photography is all about learning exposure, technique, composition, and how to work with your DSLR and your lens to nudge all of the above into optimal performance.
To those, by the way, who say "My shot looks great except when I look at it at 100%", there are some easy answers. First, all digital images look a bit soft without sharpening, contrast, and maybe some saturation. Second, each lens has its "sweet spot", the range of apertures that yield optimum sharpness (typically f/5.6-f/8 ). Third, if you are hand-holding, stop posting about it on the InterWebs and start practicing good technique, which should include the use of a tripod, cable release, and Mirror LockUp if you want to see what your camera/lens combo is capable of, as well as good techniques for hand-holding.
So, let's scurry out and take pictures, practicing the things we are learning. Read "Understanding Exposure" by Bryan Petersen, and spend some time browsing the Stickes, especially ones at the top of the Talk About Photography sub-forum, learn something useful, then take more pictures, then come back to the "Why Do My Picures Suck?" thread and update us!