I write several comedy headlines a week for a site called Newsbiscuit in the hope that at least one of them gets picked. I had some success a couple of weeks back, but nothing since then.
All contributors give votes out of 10 for each headline or news piece and the best (in the editor's opinion) are selected each day.
Today I submitted two, one of which received 8/10, the other 9/10. I was hopeful, but eventually disappointed as neither were selected. Looking through the ones that were selected and their scores, it seems that today just wasn't my day. The quality of the submissions was very high and the editors had a large number to choose from.
Sometimes it's that way with novels and short stories too. When I submit a story and it gets rejected it may not be the quality of my story per se, but the high quality of submissions at that time. The editor had to make a choice and I lost out.
At least that's my story: and I'm sticking to it.