But there's something about the short story that can blow way all those reasons: if you don't like, you shouldn't write it. This is a personal belief on my part. There are writers who excel at short stories but write crappy novels. There are writers that can produce a rich series of novels but cannot bring that same level of skill to a short story. I'm part of that latter group.
Am I talking trash about short stories because I haven't been able to get mine into print? Is this an attempt to cover up some hurt feelings? No. Granted, my short fiction has been rejected every time, but those rejection letters were always profession and in many ways filled with encouragement and helpful pointers.
The problem is that a short story bores me too easily. Because of the short length of the form, they generally cover brief plots. Any of the Harry Potter books wouldn't work as a short story because they're too complex and intricate. However, a story about a girl stressing out preparing Thanksgiving dinner for her visiting relatives or a guy trying to cover up the accidental murder of his girlfriend's pet bunny could work. They're short scenarios that can be resolved fairly quickly.
I'm a complicated man and I like my stories equally complex. I like it when the pieces fall together and I get a natural high when I do that for someone else in my work.