In this talk, scheduled directly before Erik's "Objects as a means of distraction", we'll look at the purpose and benefits of creating abstraction boundaries in software. Abstractions can be a wonderful tool to contain and control complexity. In object-oriented programming languages, objects are the primary means of creating abstractions. Some objects, unfortunately, fail to provide a proper abstraction boundary, acting instead as a rather arbitrary place to put some code and data. Such objects create and compound complexity instead. We'll see if and how we can turn such leaky abstractions into proper abstractions that live up to their promise.