Before we start, I have this one question, what is your priority for designing? Is it the look and feel, the cool animations or the information?
Personally, for me it’s the UX or user experience. I always feel that a design can look amazing and yet at the same time be functional; giving the user the optimal experience.
By definition UI or User Interface is the space where interactions between humans and machines occur. While UX refers to a person’s emotions when using a product, system or service.
UI is very important and there have been many cases where a website UI has changed causing an effect on the UX. Facebook is probably the guiltiest of changing their UI for the worst and then its just become something we have to live with. Digg is another example of this change; if you have never heard of Digg that might just be the reason. They were a major competitor to Reddit but after a UI change, they saw a mass migration of users over to the more user-friendly Reddit.
UX is one of the more important elements when it comes to design, not only in website and apps but also print media. Even the advert you see when you are flipping through a magazine must lead the viewer through an experience. The design should highlight key areas, namely the areas that you want the reader to focus on. Instead of throwing information at them with the hope something in their brain will click.
The success to any design is when your UI causes amazing UX.