There's a well-known phrase in the fashion industry: “Blue and green should never be seen,” together, that is. Well, nowadays that would be considered old-fashioned and de rigueur. In today's interior designer circles, there are very few rules when it comes to incorporating colour in interior design, it all depends on how you use them.
There are however, a few constants to do with colour theory. Research has shown for example, that cultural differences can make us respond in different ways, but the overriding and universal agreement, is that one way or another colour is important to us all.