Why is design is such a difficult concept for people to grasp? The word is bandied about without question as to what it actually is . I'm a designer and I ask a lot of questions. This one has bothered me for a while, and although I don't expect to find a simple answer, I need to think about it awhile.
In 'Zen & the Art of Motorcycle Maintenance', Robert M Pirsig asserted that whilst everyone knows what 'quality' is, it is impossible to define. 'Design' is perhaps the opposite.
For me, design is solving a problem. So a thing that does a job has been designed. You can assess how well it does the job by asking 'what is this supposed to do?' and 'does it do that?' Tin opener, jet engine, centrifuge, all do something that can be closely defined. So what about a wallpaper? It would stick to the wall irrespective of the pattern, or design imprinted upon it. Its function is independent of the decoration. A beautiful tin opener that doesn't work is useless. And annoying - I have one.
The process of making a decorative pattern is so different from making a functional thing that it warrants a discrete word. Fashion designers need to make sure the clothes are wearable, but their true function is to attract attention in varying degrees. There are lots of ways to do that.
I'm not saying decoration and fashion aren't of value, but that they don't utilise 'design' in the same way that, say, a mechanical engineer would. We need a good word meaning 'make it look good'. I'll leave that with you...