• Those who have never designed anything visual (web, print, or otherwise)
• Those who think 1996 design trends are still hot. 
• Managers, executives, etc who have no design experience but like to dicate creative direction simply because they can (or feel obligated to)
• Moderately savvy users who are highly opinionated and feel since they use the web they have an "edge" in the area of design. These clients usually take up the most time yet end up having the worst websites

So who are the right kinds of people?

• Anyone with an eye for great design, no matter what their job title is
• Usability experts who offer advice that has actual experience behind it
• Those who offer constructive criticism.  My favorite example of the wrong kind of criticism is when someone says "it doesn't feel right." 
• Those that understand that they hired YOU, the designer, to create something great. They may understand their business better, but ultimately they've left their trust with you to deliver a quality design.  

But spending more time on it means it'll get better, right?  Not necessarily.  I was in Rand's office the other day showing him the new business cards I was working on for SEOmoz.  I told him I wasn't too happy with them and had spent the past hour re-arranging bits of text and icons on a half dozen versions of the cards.  He took one look at the cards and was blown away.    From there a new term was born:  DESIGNER-ITIS (pronounced like meningitis).   "Designer-itis" is my made-up disease that designers suffer from when they've been staring at something for way, way too long.   Let a few people mull over your design for a few hours and watch it spread like ebola.  

Comment ruiner un design Web (read this post in French!)