Some great thoughts Greetje!
I think Catherine has great style. She is an absolute master with colours! There are a few more sites with women that are far more outrageous than her. They are aware of that themselves but love the way they dress so don't really care what everyone else thinks.
I also mainly dress to please myself, because if i don't feel good in an outfit, it doesn't really matter if others feel it's great, it still does not work.
The opposite is true also. If I wear an outfit I feel fabulous in, it doesn't really bother me if others say it's not nice. In the end we all have different tastes. Although, of course, I would rather receive compliments!
But you are right. If you chose to wear something, you will have to wear it with confidence. Without that it will never look great. I think that this is the exact same tip that Tim Gunn also mentions in his book; if you don't feel confident, fake it!
An article on confidence has been in the planning for quite some time now, but I just don't seem to get around writing it. I think it's one of the most crucial elements of great style!