Most fun I have had in Games (in no particular order):
Halo MCC, Terraria, World of Warcraft, Mario 64, Mario Kart (Multiplayer), Red Dead Redemption, Ridge Racer, Skyrim (SE), Witcher 3, Gears of War 3 & 4, Half Life 2, Prototype 2, Vampire The Masquerade Bloodlines, Thief Deadly Shadows, Deus Ex Invisible War, Tomb Raider 1 & 2, Sonic the Hedgehog (1), Unreal, Max Payne (1), EA Hockey, Far Cry, Quake 1 & 2.

A thing I dislike is games that force you to install Multiplayer, when you will never play that titles Multiplayer. Some titles get massive updates wasting disk space & bandwidth.