Numerous usability studies conducted by top agencies indicate that main properties of effective user interface design are simplicity, ease of navigation and effective information architecture. True, while many other factors play a significant role, few can be a detrimental factor in how application is received by the users. Assuming all functional elements of the application are working, good design and nice graphic style by itself will not make software any more usable.
To significantly improve main usability aspects its important to think of application as an appliance. Can you operate microwave with your eyes closed? Same should apply to program in sense of of ease of use.
Over the last few years penetration of user interfaces of various applications in daily lives is becoming more and more visible and noticeable.
Despite common assumptions that users by default are not proficient, general level of users is gradually growing. Nevertheless, applications are still be designed for general user not familiar with the application, technology. Users are not familiar with application ui design and need to learn it quickly. User interface should be designed with this in mind making learning curve not too steep. Training and presentation technologies became easy and affordable spurring growth in education and mentoring fields in all industries. This has adverse effects on the UI design as users often rely on the training as opposed to good usability.