Each product is built on providing a value proposition to its consumers. What you as a product wants to be and how you are perceived by the customer has to be in sync.
If Uber will not provide you a cab, what will you do with its app? Its value proposition is the premise of providing cabs on a tap.
At the same time if facebook had a shitty interface to access, add, connect with friends no one would have spent their time on it. People switched from myspace and Orkut to Facebook because the user experience was a big change.
I was reading the book written by Hari and liked the part where he mentions while we were focusing on inventory management, our competitors were busy providing a sexy user interface.
Early days of product development requires absolute focus, getting carried away is easy. Once you have a product value proposition sorted, what to focus when in product development journey becomes easy and impactful.