Joe, I wholeheartedly agree. Consistency is key in any ‘successful’ UX.
I’ve been working on a set of UX principles I call BASIC UX (see article). Which stands for “Beautiful”, “Accessible”, “Simple”, “Intuitive”, and “Consistent” — Would be great to get your input on that framework.
Something that I am finding while creating the BASIC UX framework is that ‘Consistency’ is the one principle that enhances all of the others. Whereas, pushing “Beautiful”, for example, can work against something being “Accessible” or even “Intuitive” in some cases. So, emphasizing consistency is really key in all good user experiences, and many times has the side effects of enhancing the beauty, accessibility, simplicity, and intuitiveness of a systems UX.
One example of this indirect benefit can be seen in traffic signs where the main emphasis is accessibility and consistency. The indirect benefit of this consistent accessibility is a relatively pleasant aesthetic, and simple / intuitive ‘UIs’.