Some scholars have devoted some time to considering how humor works, and have developed theories explaining it. Perhaps the most supported and useful is known as incongruity theory, which asserts that humor "results from the experience of incongruity and its appreciation or resolution." For example, stand-alone jokes work because they simultaneously evoke two seemingly unrelated systems of expectation. The "punch line" bridges these systems to resolve the incongruity. We experience pleasure in making an unexpected connection within this resolution. Such a connection has been likened to the feeling associated with solving a puzzle, and to cognitive "play." Incongruity and its appreciation exist in comments, quips, puns, and other behaviors, not only stand-alone jokes. Sarcastic comments contain incongruity between what is spoken and what is intended. Violations of social norms are incongruous in expected, versus actual, behaviors.