* AlternateCharacterInterpretation: The story could easily be seen as Bob the JerkAss tormenting the stressed-out Dr. Marvin while everyone is too stupid to realize Bob is actually not as wonderful as they say he is. On the other hand, Dr. Marvin has legitimately pissed off a lot of people and screwed up his own family, and Bob is a pretty nice and well-meaning guy underneath his mental issues.
* RuleOfFunny: The film's outlandish premise and [[UnfortunateImplications unfortunate implications]] (see below) can be looked past depending on whether or not you found the film funny.
* ThrowItIn: The scene with Bob entertaining the nursing staff at the mental institution was unscripted -- Bill Murray was just having fun.
* UnfortunateImplications: While Leo certainly is a JerkAss, Bob's actions, innocently intended or not, would generally be considered, at minimum, a gross violation of the patient-professional relationship, and probably criminal harassment, invasion of privacy, and/or stalking. This makes the rather sympathetic portrayal...problematic.
** FridgeBrilliance: The above makes you wonder why Leo doesn't just call the cops on Bob or file a lawsuit against him- until you realize that Leo is so concerned about not looking like the bad guy to his family, who already have significant problems with him and are conversely enjoying Bob's company, that he's effectively prevented from doing anything like that.
* TheWoobie: Bob. Honestly, he doesn't necessarily mean to drive other people crazy because of his craziness. And you have to wonder what happened to the poor guy to make him so unbalanced and phobic in the first place.
** JerkassWoobie: Dr. Marvin may be an obnoxious JerkAss, but one can't help but feel sorry for him considering everything he suffers at Bob's hands over the course of the story.