Most places that use Submitable say that the cover letter is entirely optional, so I usually always include my contact information with the manuscript. However, the other day I was going to submit a piece and in the instructions it said that the only place for contact information is in the cover letter section, and that any manuscript that includes contact information will not be considered.
Have I been fucking up by including my contact information with my manuscript?
Some journals only read anonymous submissions, therefore they would not consider a manuscript which includes contact info. Whether or not you're right to put contact info here or there would vary.
"So the editor had less to look at"? Seems odd. It's a cover page. You can flip right past it, no matter how many letters are on it.
Standard manuscript format for short stories includes your contact information on the first page. So, I do that unless the market has specified other format.
I agree, you can include it unless the guidelines say otherwise, but YOU MUST READ THE GUIDELINES. Many markets will tell you that they read blind, and your piece might be automatically rejected if you don't follow their guidelines to a "t." In the very least, it will appear that you have poor comprehension or just didn't care, two things not generally considered in your favor.