Has to be composition. You can take a picture of anything and, in theory, make it look interesting, but I seem to have difficulty making shots that are something other then a documentary style. A capture of life and events as they happen, landscapes, etc are where most of my shots are focused. Mundain objects and still life either look 'traditional' (fruit in the window composition, etc) and therefore, in my eyes, cheesy.
My bigest problem is wanting to center everything. I am very anal (I am the person who would straighten a crooked picture on your wall in your home. I can't help it, it would drive me insane and it has caused me to have an anxiety attack to not do it)and I prefer to center but, everyone says that is a big no-no So I am trying to break this habit but, it is so hard.
I consider myself patient in waiting for the best light, so it is not much of a problem for me, nor is color or contrast, due to Velvia, and post processing. I generally think that composition is the hardest trait for me. I have a hard time breaking out of a certain mold in my landscape photography. I think I have a hard time concentrating on the more intimate details of the landscape, as opposed to simply the big picture.