From Halopedia, the Halo wiki
Delighted is an achievement in Halo: The Master Chief Collection. It is awarded for activating the ninth Halo 2: Anniversary Terminal on Quarantine Zone. The achievement is worth 5 Gamerscore and can be unlocked on any difficulty.
The terminal is found in the first large room in the crashed Sentinel manufacturing facility. It is on the lower level, beneath the platform on the far side of the room.