No matter how cool your user interface is, it would be better if there were less of it.

This quote belongs to Alan Cooper, one of the pioneers of UX design, also known for his books About Face: The Essentials of Interaction Design.

Designers often overwhelm user interfaces with unnecessary functionality and forget about the main problem that they try to solve — the user problem. Nowadays, we have hundreds of ways to solve user problems without designing a mobile app. Try to think about the problem you try to solve, not the technological solution.