There are many different queueing policies, and they tend to be defined in model-specific ways that differ in form from policy to policy. While each form is suitable for the task at hand (e.g. steady-state derivation, scaling-limit theorem, or proof of some other property), the specificity of the policy definition can sometimes limit the scope of what are often quite general arguments. Moreover, because policies are defined variously, it's difficult to approach classification questions for which the answer presumably spans many policies. For example, consider the question "What conditions on a policy guarantee the existence of a fluid limit?", or more generally "What class of policies have property X?". For such questions to be precise, it must be understood what is meant by "policy". If this is defined too narrowly, then in a sense a class has already been specified and one can only check property X for that class. In this talk I'll propose a definition of a general queueing policy and discuss exactly what I mean by "general". The setup makes it possible to frame questions about queues in terms of an arbitrary policy and, potentially, to classify policies according to the answer. In this vein, I'll describe a few results and some ongoing work on the question of fluid limits.