In order for software to make sense, it needs to have a valid reason to exist. That reason has to have its roots in the needs of the Customer. In turn, it needs to be clear that the Customer is a Human in the end, with their tasks that they need to complete - the utility.
Coherent User Experience enables this utility, completing of these tasks with great usability. It is approachable at the same time.
In touch with the real world
There is an important balance point between real-world feedback and expert opinion. Early prototyping and involving actual users is critical for success. This is at the core of Lean UX. At the same time, end-user feedback cannot be the only thing guiding development. After all, it's only human to try to fit new ideas into patterns that already exist. A problem arises when new ideas do not fit any existing pattern.
It's good to be aware of this and push the envelope the right amount. New ideas can unlock dormant needs or flat out spawn new ones. This is where software starts becoming significant and purposeful.
That extra mile
Actual usability is important. It lets you get things done. Even better if all that can be nice and easy. This is where perceived usability steps in. at best interaction makes the user feel more productive than they actually are. More often than not, defaulting to UX conventions is the way to go.
In specialized User Interfaces, things can often get complex. Tweaks to the convention are inevitable and require careful design. We always aim for the simplest solutions, all the while maintaining a stunning baseline of UI design.