Story rejections happen for a number of reasons. Here are a few, in no particular order. ~The story really does suck. (This was not a problem with "Why Pete?" because the judges at WOTF are very picky.) ~The story is of a type which doesn't appeal to the editor. (He/she hates space operas, or whatever.) ~The story is not a good fit for the publication. (The story is science fiction, the publication is Homes & Gardens.) ~The publisher has recently purchased and/or published a similar story. (Just bad timing.)
As a Canadian writer of stories of a speculative nature, including science fiction, fantasy, and horror, it has been one of my goals/dreams to have a story appear in Tesseracts, the annual Canadian Spec Fic collection.