"If you wish for peace, prepare for war"- Publius Flavius Vegetius Renatus's
When a neurosurgeon is performing an operation on the brain, you will not see any of the hospital’s business management personnel trying to advise him what tools to use and where to cut. But when a professional designer tries to replace one type of font with another or use a slightly different color in the presentation/website, etc., then often we see a lot of hands from the so called “professionals” specializing in business of visual communications by mostly drawing the little funny pictures when no one sees them.
Each one of us has had plenty of these kinds of frustrating experiences. Just ask any of the leading designers or creative professionals such as Paula Sher («Make It Bigger») or Stefan Sagmeister - if they would work with a client who tries to tell them what colors to use in their work.