Yes Man

 is a securitron robot found in the Mojave Wasteland in 2281. He serves as Benny's assistant and can't help but reveal the end game scenario for New Vegas in excruciating detail. He was programmed by a member of the Followers of the Apocalypse to answer all questions that he was able to answer and assist in any way he can, but was never given any restrictions about who would be able to ask him questions in the first place, allowing him to help the Courier.

Background
Yes Man was originally a generic securitron robot working for Mr. House, like all the other securitrons found on the strip. He was seemingly damaged, possibly intentionally, and then recovered by Benny. He then allowed a member of the Followers of the Apocalypse to examine the securitron, in exchange for repairing and programming the securitron.

The player can later pass a science check of 80 with Fisto to reveal the sexual exploits between Benny and Yes Man

Interactions with the player character
After speaking to Mr. House, the Wild Card series of quests will begin. From this point onwards, the Courier will be able to go up to Benny's penthouse in The Tops Casino. There he will find Yes Man. Yes Man will explain what Benny's plan was; to dispose of Mr. House and plant Yes Man's A.I. in the Lucky 38 mainframe. The player can then choose to continue Benny's plans, and start the Wild Card: Change in Management quest. If you have killed Benny, Yes Man may appear outside the tops casino, near the entrance.

Should the player complete the wild card quest, Yes Man will take Mr. House's place in the Lucky 38. After the assault of Hoover Dam Yes Man informs you that he found a crack in Mr.House's design that, in his words, "changes my personality" and says he will look offline for a little while until his personality change is complete. (He never actually shows his changed personality due to game ending) However, Yes Man clearly states that he's going to be more "assertive."

Appearances
appears in Fallout: New Vegas.

Behind the Scenes
'A Yes Man' is a phrase used to refer to someone who will only agree with his employer or superior.

In other languages he might be named Servibot because of his "need to serve".

Yes man is voiced by David Foley

Trivia
Doing a Google search of the term 'Happy Face', reveals that the first result is the image used for 's face.

if the player attacks he won't defend himself but will say :"it must be my fault" and when he die he'll say :" whatever i did, i'm sorry"