Reinventing the wheel is necessary

While providing justification for UX decisions, we usually refer to authorities, market trends, what big successful players are doing etc. This is definitely a valid approach, but it does not provide the deeper understanding of what drove the creator's thinking. The creator's consciousness is always much higher than the imitator in the chosen area. Usually design principles are closely tied to psychology (behavioral psychology, gestalt psychology, habit psychology etc.), science of perception, cognitive science on how we form mental models etc. Therefore an understanding of these areas gives you much more profound knowledge on what drove the creator's thinking towards those designs.

Your daily job may require you to make quick decisions and may not give you the time to explore in this depth. But nevertheless, to be a pioneer, to speak with genuine confidence, it is necessary to understand the real root behind design decisions which lies in exploring the above mentioned areas.

Abstract: For the UX Role

In my experience, I have observed the term 'User Experience' could mean a whole myriad of things. When you work as a UX Designer, its not just UX that you do.

Its taking into account and satisfying requirements from multiple areas:

1. Business Goals and Strategy
2. Maintaining Brand Image and what it represents
3. Maintain reasonable consistency with existing momentum (In terms of visual design, processes, methods followed, team culture etc.)
4. The User Goals (derived from surveys, experiences of employees dealing with customers, News, direct user interviews)
5. Aligning Priorities based on Deadlines, Project Timelines, Development Timelines etc.
6. Collaboration with other team members and adjusting to the work styles/Meeting culture/Getting consensus
7. Market Trends/Habits setup by Big Giants such as Google, Pinterest, Facebook, Twitter, Linked-In, Instagram etc.
8. Mandates coming from above - CEO, Executives with business ideas etc.
9. Ensure that there is a steady flow of projects for you to do on a day to day or week to week basis (if not, you have to find something to do) 
10. All the perspectives that created the existing design (in case of building over existing products). This would be needed to fit new pieces into the existing jigsaw such that its in harmony.
11. Seeking balance between:

• 'Time spent on Brainstorming (to get a wider and deeper picture)' and 'Getting something actionable out of it (so that things can move forward at a competitive speed wrt. market)'
• 'Putting effort into detail' and 'Getting something out in the market quick'
• 'Building a fully finished module or project (compromising early feedback from users)' and 'Moving big projects in phases, measuring each step and letting things evolve organically (agile method, compromising long term vision to an extent)'
• 'Imitating what competitors/big businesses are doing (Creating comfort for the users by familiar interfaces, but nothing stands out as novel)' and 'building something uniquely tailored to your company's vision (May be too deviant from market trends)' 
• 'Creating user retention strategies' and 'Creating a lot of annoyances for the user'
• 'Marketing new features, promotions' and 'Reducing the irrelevant information, annoyances and distractions from the primary use case'

The balances part of it could be looked at more abstractly, as balance between:

• 'Exploration/Playing with Clay' and 'Decision making/Solidification'
• 'Completeness and detail' and 'Quick and Dirty approach'
• 'Doing everything in one pass' vs 'Staggered approaches/Do, Measure, Learn cycles'
• 'Imitation/Conformity' and 'Novelty/Deviance'
• 'Persuasion' and 'Aggression/Annoyance'