Reign Over Me
Reign Over Me, a rare dramatic turn for Adam Sandler, is a movie which stars Don Cheadle as an discontented dentist who finds new purpose in life when he meets up with his long lost college roommate, Charlie. Falsely accused of adulterous passion (like Joseph in the Bible), Alan finds new inner strength as he devotes himself to helping Charlie face the reality of his deep sadness over losing his family in 9/11.
Bereft of his wife, daughters, and even the family dog, Charlie Fineman has isolated himself with virtual reality games like Shadow of the Colossus, record collecting, drumming, and obsessively remodeling his kitchen. He wears Bose Quiet Comfort headphones and putts around on Manhattan on a fuel-powered mini-scooter. His landlady and accountant shield him from unwanted visitors. He has quit dentistry and is living off the insurance settlement from his family's deaths.
He is so cut off from his sadness that he literally does not recognize Alan Johnson, despite sharing two years with him in dental school. He refuses to entertain any mention of his family, professing never even to have had one.
Alan gradually reintroduces Charlie to reality, even as Charlie tries to get Alan out of his shell. They stay out late at night, overdose on "Mel", and ride tandem on Charlie's scooter. Charlie encourages Alan to stand up to his unsupportive colleagues, while Alan struggles to get Charlie into therapy. The film's climax comes when Charlie finally lets his suppressed thoughts of his family emerge.
Charlie uses noise-canceling headphones (with or without his iPod), an ugly Dylanesque appearance (poofy hair and an unstylish long jacket) to insulate himself from any contact or reminder of the upper middle-class world where he enjoyed life with his adoring family (a wife; daughters age 5, 7, and 9; and a small dog). He tools around Manhattan on a motorized scooter which he uses for quick getaways from unpleasant encounters. 
Johnson's situation is the photonegative of Charlie's. Charlie gave up dentistry after 9/11, Johnson is the leader of a clinic with 4 other dentists. Charlie maintains a disheveled appearance and hides in his apartment fiddling with his record collection, remodeling his kitchen, playing Shadow of the Colossus or behind a drum kit in a seedy club playing rage rock; Johnson's grooming and apparel and demeanor are so attractive that women are constantly hitting on him at work. Charlie apparently only knows three people: a landlord and lawyer who enable him to stay isolated, and an exploitative bar owner; Johnson knows many people but is not emotionally close to any of them: he's the classic Man From Mars with his wife, never listens to his daughter, gets blown off by his receptionist, and his dental partners refuse to back him when a patient threatens a bogus sexual harassment lawsuit.
When Johnson spots Charlie after 5 years of rebuffed contact, it takes him two tries to connect. Johnson is surprised that Charlie doesn't recognize him, and it takes quite a bit of effort to convince him they were once friends.
Attempts by Johnson to bring up Charlie's dead family result in outbursts of rage and violence from him. The first time, in the seedy bar where Charlie plays the drums in a band, teetotaler Charlie demands "Who sent you?" and throws root beer in Johnson's face. The second time, he trashes Johnson's dental office. 
Johnson has been trying inappropriately to get informal psych help from Angela Oakhurst, a (young) lady therapist in his office building (Liv Tyler, who played a PhD. psych student in Jersey Girl and apparently graduated in time for this movie!), describing his own situation in terms of a 'friend'. After fruitless attempts to help Charlie himself or set him up with a middle-aged (male) therapist, he gets her to take him on. Their sessions are short, and Charlie ends them the moment she asks any questions about the "thoughts" he's been avoiding.
- Only love can make it rain ... Love, rain on me (reign over me).
The song expresses both rage and despair. In it love is seen as an antidote to dust and heat (cool, cool rain) - and also as a welcome ruling force (reign o'er me).
Torn from the love of his family, Charlie becomes depressed and shuts out all the pain with drumming, collecting old LP's and a 3-D video game where he must climb towering heights to destroy monsters. ("Monsters" destroyed New York's tallest towers and killed his family).
One day he finally opens up to Johnson (overheard by Oakhurst) and shares about his family. This seems good, but shortly thereafter he tries to commit suicide by cop but a member of New York's Finest blindsides him, tackles him, and the two cops slam him against a wall three times. The city decides not to press charges against a "9/11 widower beat up by two cops" but insist on a 3-day psych evaluation. Charlie is released, thanks to Johnson and the lady shrink but must attend a hearing.
The hearing is a classic Hollywood gimmick, complete with a shrewd and sympathetic judge, an emotionally manipulative prosecuter, and a "clear the court" scene followed by a dressing down in the judges chambers. "Do that again, and you'll spend hard time in prison. Now just shut up." And, "Don't bring Sugarman."
The film ends with Fineman hesitantly but forthrightly speaking to his in-laws about "seeing" his wife, kids and dog in strangers he encounters - which for him are even more vivid reminders of the photos his father-in-law carries in his wallet (and which were used by the prosecutor in the hearing to provoke him into 'crazy' outbursts).
Finally, Johnson conspires with Fineman to help him move out over the weekend (before the final hearing, which never transpires). Johnson meets the in-laws at the empty apartment, which is spotless and has a beautifully remodeled kitchen, and asks them to let Fineman go. They agree. Then Johnson sets up Charle with the lady patient who had threatened the lawsuit, hops on Charlie's scooter, and heads home to his family.
- The scooter itself is just powerful enough to make it technically illegal in New York City, which permits electric scooters but has banned engine-powered ones like Charlie's. He's a bit of an outlaw.
- What he destroys here is symbolic of his grief: pictures torn from the walls, and lamp like his mother-in-law's favorite.
- Editor Jeremy Roush explains, "You could see where someone who was dealing with 9/11 would be engrossed by a giant that keeps collapsing over and over again."