In the "Person of Interest " episode "Many Happy Returns," viewers saw another side of John Reese (Jim Caviezel). We saw that Reese is capable of losing his cool in a big way. Fans did see him lose his cool once in the episode "Baby Blue," when he gave up information to save a little baby; that was just a momentary lapse, however. In "Many Happy Returns," we learn of three new ways to make John Reese lose his cool.
Kill someone John Reese cares about.
John Reese has always been fighting for others. He used to be a Special Forces soldier and was always off fighting an important war somewhere. He rarely had time to be with his girlfriend, Jessica (Susan Misner), whom he loved. He thought she would be better off with someone who was around more often to protect her.
Unfortunately, the man she found, Peter Arndt (Jonno Roberts) was not there to protect her. He was the sort of monster from whom Reese protects others. After Peter killed Jessica when beating her, Reese went into a tailspin. We do not see what he actually did to Peter, but it did not look good. This is what caused him to begin living life as the homeless transient we saw in the "Pilot" episode.
Kill a person who reminds John Reese of someone he cares about.
When Karen Garner/Sarah Jennings (Dagmara Dominczyk, who played opposite Caviezel in the 2002 adaptation of "The Count of Monte Cristo") tries to escape her violent husband, U.S. Marshal Brad Jennings (Jeremy Davidson), Reese loses his mind right off the bat.
Reese decides to severely beat Jennings, along with some of his law enforcement buddies, causing a larger problem than he started with. Reese is usually very efficient, so this is far outside the norm for him. He not only causes Jennings to lose his cover and take Sarah hostage, he also risks attracting attention from the federal agents he is trying to avoid.
Don't tell John Reese that a bad guy is about to kill a person who reminds him of someone he cares about.
We see Reese acting very coldly toward Finch (Michael Emerson) for the first time. This is because Finch fails to tell him that there is a new social security number, giving Reese the day off for his birthday instead. Finch feels he is protecting Reese from the situation that will remind him of what happened to his own girlfriend, but it is perhaps not the best idea. Reese is resourceful, and figures out what is going on.
Finch redeems himself by honestly explaining why he did what he did. Reese does not agree, but his anger toward Finch seems to subside quickly. Reese's anger subsides even more when he opens his birthday present from Finch, a beautiful new apartment overlooking his favorite chess games on the street.
Image source: "Many Happy Returns" Reese (Jim Caviezel, left) and The Machine's latest number (guest star Dagmara Dominczk, right), PERSON OF INTEREST, Thursday, May 3 (9:00 - 10:00 PM, ET/PT) on the CBS Television Network. Photo: Barbara Nitke/CBS ©2012 CBS Broadcasting Inc. All Rights Reserved