What you should have known...
...Before Posting that comment
on the newest DD that you thought was "undeserving" of a DD.

Daily Deviations are a 24 hour feature. Nothing more.

GMs select DDs based on their own feelings towards a piece of art. As artists themselves, they do not always reflect every deviants beliefs and views of art
1.

A deviant receiving a DD does not have any say in the matter. In fact they probably didn't know they even had a chance at getting a DD!
...Before sending that GM a disrespectful note
about their newest given DD.

Gallery Moderators are volunteers

GMs are human just like you

GMs feature art they think is amazing. If they featured it they had a reason behind it.

Using Swear words and disrespect tends to get you ignored instead of an answer. Try writing a GM with respect.

Try seeing it their way from time to time. Perhaps the DD you dislike is actually amazing but you just haven't had a chance to look at it a certain way.
...Before writing that disrespectful note/comment/journal
about that new Daily Deviation.

It's against dA Policy and Rules to be disrespectful!
2
It reflects badly on you. What you write will be seen by many other deviants and you will be viewed as a disrespectful deviant.

There is no need. If instead of spamming disrespect and hate, you simply wrote the GM Respectfully, it would all have been taken care of already!
...Before disrespecting that Gallery Moderator

GMs are Volunteers (Yes I said this already, it's something you need to remember)

They have taken hours and hours of their life in order to help this community

They were hand picked by $
Moonbeam13 which means they can't of been horrible as they would have never been chosen.
...Before writing that dA Hate Article
that you recently posted or commented on supporting

Hate articles (or rant articles) don't help anyone.

Hate articles incite 'violence' and do not help the community improve.

Writing to the Help Desk, The Suggestions forum etc. is the correct thing to do.
...Before complaining
about anything.

You SIGNED UP for this website.

You can leave at any time.

You have to log in every day in order to complain

So you are already contradicting yourself by complaining.

No one enjoys listening to complaints.
...Before complaining that the dAr Category isn't art
and writing disrespectful comments to that effect

The deviantART Related Category is there to support the 2nd half of dA. It's Community.

In order for you to have written that disrespectful comment, you had to click on the deviation. Next time, just don't click on it and ignore it.
...Before having done anything like this

Consider what it might cause, weigh if that outcome is really worth it

If you were going to just Complain/Be Disrespectful etc., find out if there might be a better way to discuss the issue such as contacting the Admin or Volunteer who has concerned you or making a suggestion.
References
1 I have talked to deviants about all types of art including whether or not things like Comic Strips and Garfield (for example) are art. Some people say they are, others don't. This is the view I am speaking of.2 See "Prohibited commentary is typically considered to be inherently disrespectful, aggressive, or otherwise abusive." Etiquette Policy as of January 15, 2011.
There are other ways to show dislike, sometimes the best way is to just ignore it. You don't ever have to click on a thumbnail you don't like.
Thanks to `
PurpelBlur for his feedback as well as suggestions for this article and proof reading prior to it being posted.
However I do think that, while you're giving us valid points, you probably worded out a few things wrongly and got some things wrong.
DDs aren't just a 24-hour feature. They never were. They'll always be there for people to see because you can browse through previous days to see past DDs anyway. Deviants who receive DDs would still get exposure. Just how exactly is that "nothing more"?
And I didn't sign up to deviantART to know that I can't complain about anything about this site if I don't like it. That's really restrictive and almost dictatorial. I'll complain what I find horrible and love what I like, thank you.
Just my two cents.
So, you get a DD, and someone comes onto the page and says, "This is undeserving." or a really rude, distasteful comment. So WHAT? It's a comment! Just ignore it. Two wrongs do not make a right. Just simply ignore the hate. Those people will usually drop it anyway. Though, if they are HARASSING their opinion onto other people, then it's time to put that person in the right place in this situation.
You are way more immature than the commenter to reply with equal anger.
I also say that alike so many people on this article, I know DDs are more than just 24-hour features. You can go check them out ten years afterwards if you feel like it! They're right there, in the "browse DDs" section.
Also. People don't only look at that one picture, they roam the deviant's main page and possibly even a gallery and if things go well, the deviant receives not only ten thousand favorites but also a few hundred watchers. Now if this is "just a 24-hour feature", we should just get rid of the DDs and all this drama and bullshit or make it into a system that actually works.
TL;DR: Please don't make hate-articles about people having opinions and please, if you just could, try being polite and respect others' opinions. Otherwise, I'm afraid it's best if you left Da and searched for some "better" site.
I am hoping to receive an unbiased and respective reply. But in case none can be provided, I hope you'll do as you told others to do, and not reply at all.
So if you tell the featured deviant that their work is bad then you're just being a prick and if you send the moderator who featured the deviation a nasty note, again, just being a prick!
We all have work that some people don't like and we all have
Around here, honesty and politeness is everything. Kids get taught to tell their opinion, omg, in a polite manner(aka not being pricks since not telling whether something can be improved is just wrong). If you never speak your mind, absolutely nothing will change, that's just common sense.
About being an idiot when commenting:
So if you tell a featured artist that their art is "the best" no matter what level their skills are on but don't tell them that they have room for improvement, you should really deserve a big kick in the balls, preferably with heavy shoes. You give someone the illusion that they're WAY better than they are and they're less prominent to improve. Much less.
And yes, criticism is telling people what in their art went wrong. Telling "your anatomy is off", "the light-source is unclear", "the arm's muscles are reversed" or "That pose looks bad" isn't wrong unless you're a complete bitch about it(aka: trolling). Unless you're trolling, you're being 100.000% more helpful than any "omfg tis awesome"-commenter ever was.
Just my two cents.
If you took that as me calling you a prick then you took it of of context, unless you have done the whole "This is shit and not worthy of a DD" thing. It wasn't directed at you, just the people who do it
Just giving my opinion as you weren't clear on the whole lot in your main comment, all cleared up in this reply though
I didn't take it as calling me prick, I took it as calling everyone who's ever said anything negative towards a DD, a prick(if you didn't mean that every negative comment is "being a prick", I apologize, that's just the image your reply gave me). I've never said that some "shit" doesn't deserve a DD, although I have said that I don't understand why something got a DD because honestly, every day there's at least one DD that's clearly not DD-material. Why some people feature them is a complete mystery to me.
I thought I was pretty clear in my first comment but if I wasn't, I'm glad the second comment made my opinion clear.