15 Lessons Movies Can Teach Us About Cheating

Lesson: Cheating offers a confusing combination of guilt and giddiness.

Sammy (Laura Linney) is a single mom who doesn't particularly like her boss, Brian (Matthew Broderick), so their sudden love affair takes her by surprise; she can't believe how much fun it is. One particularly poignant scene shows her driving home after a tryst with Brian, grinning like a school girl then slipping into "what have I done?" mode in a matter of seconds.