The user doesn’t exist. No one conforms to this abstraction. Yet, it is useful.

Many discussions on design revolve around simplicity: How can we make this feature easier to understand, how can we make this product more intuitive, how can we simplify this design?

Adding multiple user types increases the number of factors exponentially. Complexity and competing priorities appear as a result.

Successful products are strategically mono-dimensional. The interesting question is not: How many personas do we need? Rather, the question you want to answer is: Who is my user? Allowing for some degrees of freedom with respect to demographics, computer fluency, and domain knowledge, are well within the bounds of the user as a device.

Trying to make everyone happy, is a losing proposition. Tearing the user down, will make everyone worse off.

The user is a powerful construct that will help you move toward your product vision and help keep the team aligned. It will simplify most choices – for you and your users.