This is your standard boiler plate. A form email thanking you for your submission, announcing that they've decided to pass, and wishing you luck placing the piece elsewhere. The P.F.O. is professional, timely, and easily shrugged off. The majority of rejections will come in the form of a P.F.O.
The rejection you get two hours, or twenty minutes, after submitting. It's good because you don't have a chance to get anxious and eat a pack of Twizzlers. It's bad because you know they didn't read your entire story, and since no one expects a rejection that soon, it probably hit you in the ear.
The Not So Golden Silence
... *twiddles thumbs*...
The Skin Thickener, aka Rejectasaurus Rex
Sometimes an editor loathes your story so, so much that they take many minutes out of their slush filled day to compose a withering email denouncing your narrative voice, your characterization, your pacing, and your geology (true story, this dude really didn't like shale). At best you feel like a hack, and at worst you're left questioning several life choices that aren't even writing related. The maddening part is that at least some of the criticism, while harsh, usually has merit and once you finish licking your wounds* you will use it to improve your piece.
* Coping pro tip: Twizzlers are paired remarkably well with a 12 year-old Balvenie single malt.
The best rejection you can get. Most editors are overburdened with reading, so it means something when they take the time to reject in a personal and positive way. They'll tell you they loved your characters even if the story isn't right for them, or that the language is beautiful but it's slow to develop. These are the unexpected but welcome writerly hugs that encourage us to keep going. These editors also tend to be the kind who are fantastic to work with if they do accept your work.
So, my fellow rejects, there you have it. If you've experienced a form of rejection I haven't discussed, I invite you to share in the comments. Meanwhile, I'm off to the bottle depot.