The notion of goals, which tend to have strong properties (e.g. goals should be consistent, feasible, not yet achieved, etc.) has received more attention than other motivational notions such as desires. Desires seem more applicable in a multi-agent setting since an agent may cooperate with other agents without an explicitly agreed goal, but cannot act purely independently. However, the connection between desires and real world actions is not formally described. In this work, we introduce the notion of expectation in order to address these problems. A formalism is developed to describe the association of expectations and observations as well as how expectations could drive future observations.