Think of taking flight, for example in a fighter jet as being agile and armors in the jet represent security and other processes.

The armor is there to save us, If we try to fly without the armor we'll easily be shot down. But if we add more and more armor, it becomes difficult even to take-off; it impacts our ability to be agile and productive.

The sweet spot is somewhere in-between. Be weary of anyone who claims that this relationship is linear, It's not!

Note: You can use this framework to apply to other situations. This is one of the tools that can help you understand trade-offs.

References:

How Not to Be Wrong: The Power of Mathematical Thinking - Chapter 1 - Linearity