The recent work on business process flexibility focuses primarily on defining and classifying business process flexibility and developing strategies, architectures, and tactics for achieving it. However, to specify the required type and level of business process flexibility it is essential to understand how the need for flexibility arises in the first place, and how this need affects the requirements for flexibility. The objective of this position paper is to examine the characteristics of the environmental variations that provide the stimulus for designing business process flexibility and its implications for the design and management of business processes.