Systems thinking refers to the ability to understand an organization holistically in terms of the people, processes, and technology within it. When you develop your ability to apply systems thinking, you aim to understand not only the individual components within an organization but also how they are all interconnected. You look at not only the components that are isolated entities but also the people and the entire internal and external organizational environment. A key part of the role of business analysis is to analyze an entire system and all the components involved in order to have a full and meaningful picture of it as a whole.

Let's consider a real-world scenario.

When an employee decides to resign from their position in a company, it is not just a matter of stopping their salary payments after a certain date. The business analyst should analyze this process by applying systems thinking. By doing so, they look at all the components and processes, as well as other employees that may potentially be impacted by the employee's decision to resign. 

Some example processes that could be impacted and require analysis are revoking access to an office building, stopping any pension payments, re-assigning roles and responsibilities, or triggering the recruitment process for a replacement employee. All of these (and more) are surrounding processes that form part of the whole process that is impacted when an employee makes the decision to leave an organization.