[After 11 years as a game artist I have learned that there are somethings that are better left unsaid. These are the statements that I feel lead to ugly art, substandard game play experiences, or poor taste in general - semi-NFSW image inside.]
"I want it to look just like (insert Star Wars/Matrix reference.)"
Nobody wants to work on art that looks like what other people have worked on. Especially not art thats been done to death. The gaming audience doesn't appreciate copycatting either. Reach back into your bag of tricks and try a little harder.
"Yes. That's exactly what I asked for. But its not what I want."
Artists have talent, not super powers. We can't read your mind. Take a moment to gather your thoughts before barking out requests. It will save us both time and frustration. I would be happy to charge you more money for change requests, but I also have a life. Gathering reference (other than Star Wars/Matrix) via google image search is a good start.
"Can you make her boobs bigger?"
Most artists have been trained to appreciate the beauty of the female figure. So chances are she's already got enough on top. I think the old adage "More than a handful is a waste" also applies here. Even if you plan on investing in a boob jiggle physics engineer, those suckers are going to look ridiculous.
"I think it needs more blood."
Ohhhh blood. The most overused visual element of all time (next to big boobs.) What's the point of paying me for my beautiful texturing work if all you going to do is cover it in blood like Carrie. At least she got her revenge.
"Suggest that a) unexplained nudity b)lingerie c) loin cloths d)all of the above are proper combat attire."
The thought that I'm one flap of clothing away from seeing pixel junk doesn't make we want to play your game.... Sex doesn't sell video games, good gameplay does. Go back and work with the design department on better ideas before you have me work on the uncanny valley.
Ummm.... Yeah. I had to make that. Good Times!
"We need to add another level/character/feature!"
(Right before Alpha)
The time for new ideas is during pre-production. Please don't come to me (or my team) with a new request that's going to take over one man month of work a week before Alpha. We are trying to finish a game here! Besides ideas that come at the last minute are rarely good or make the game better. They are often desperate attempts to make an inconsequential metacritic point increase.
"You must have broke it."
There is a love/hate relationship between engineers and artists. We need you to make cool features, get the game to function properly, and create tech that makes our lives a little easier easier. You need artists to make your game look good. So chances are when something breaks in the game, your going to blame it on us first and check facts later. Believe me, if I'm coming to you with a problem I've crossed my t's and dotted my i's. Artists hate enduring the programmer death stare.
*Disclaimer* Most coders are nice guys. But there's always "that guy" at every company.