When designing systems we must keep people in mind.
Systems' usage goes through phases of peaks and throughs of demand.
London Underground system is a great example of a system which comes under huge demand at peak times.
At the early morning hours of peak commute, people create huge crowds.
Operators of the system must have procedures to control the crowds at these times.
This crowd control is an important part of the system design.
In perfect world we would not have these surges.
In reality, they happen with almost everything.
In Design Thinking it is important to bare this in mind and design for all circumstances.
The impact on human experience of using the system at these peak moments is immense.
People become cranky, start complaining and the commute times become much higher.
It all impacts on practical value of the system for the participants.
This sort of behaviour is present in digital experiences too.
When nobody uses the system this can be bad.
When too many people are using the system, it can also be bad.
Creating some sort of a balance is the ultimate aim.
It may not be possible in the real world.
So designers must bare in mind the reality of the situation and the distribution of demand.
Systems like Uber deal with these problems by leveraging the surge pricing.
London Underground has an element on it too, but it's a different kind of a use case.
These are complex problems to solve, but this is why Design Thinking exists.
Designers always work on dealing with complexity in as simple ways as possible.