This is the first of two essays about planning and execution with ill-defined and conflicting goals. The concept of flexecution - flexible execution - goes beyond simply adapting a plan as needed in order to reach our goals. Rather, flexecution entails changing the goals themselves based on discoveries made during execution. In pursuing ill-defined goals, we must expect to revise and even replace the goals we initially stated during the planning phase. One of my objectives in writing these essays is to describe the importance of goal discovery to planners and project managers who might not appreciate the difficulties posed by ill-defined goals. A second objective is to offer suggestions to computer scientists who design mixed- initiative systems about how to better support planning and execution with ill-defined goals. We'll begin with the notion of planning to set the stage for comparing planning using clear goals versus planning and execution using emergent goals.