It's interesting how repetitive all games are and I can still play them. What keeps me going? Honestly I'm not sure. Some or all of the following characteristics depending on the game, in no particular order: 1.Immersive/realistic environment 2.Lore/story that the player participates in, influences the outcome. 3.Variety of activities 4.Variety of roles. 5.If Multiplayer- group dynamics 6.Strategy 7.Game progression 8.Upgrades in abilities. 9.Grind (negative) 10.Reflexes (such as twitchy FPS) 11.Technical skills, mastery of knowledge (such as flying, mastery of abilities) 12.Sexual Appeal 13.Territorial acquisition 14.Open World 15.Sandbox 16.Repetitive (negative) 17.Rely on combat/killing 18.No violence 19.Situational Management 20.Static 21.Dynamic Number one, I have to say an immersive environment is a must, followed by variation of activities, group dynamics, the feeling that you are sharing this experience with other players even if you are functionally solo when in a multiplayer or MMO. When I examine the games I've played the longest, usually a year, but less than two years, they would be: *Marathon (FPS, PVE, PVP, MP-1,2,5,6,10,17, MP21)- played multiplayer feature greater than 5 years. *Unreal, Unreal Tournament (FPS, PVE, PVP, MP 1,2,5,6,10,17), MP21)-- UT is just a shooter, no story, but has PVE arena progress. Played longer than 5 years. *SimCity (PVE 1,7,14,15,18,19,21) *Civilization (PVE, PVP, MP, 1,5,6,78,13,14,17,19,21) *Planetside (PVP, MP- 1,4,5,6,8,11,13,14,17,21)- Group combat, control islands. *World of Warcraft (PVE, PVP, MP- 1,2,3,4,5,6,7,8,9,11,14,16,17,20)-Best open world MMORPG. Have played off an on since inception, this latest interaction will be short lived as I am truly burned out with it. *Elder Scrolls-Oblivion, Skyrim (PVE Solo- 1,2,3,4,7,8,14,16,17,21)- Best open world RPGs. *World of Tanks (PVP MP- 1,4,5,6,7,8,11,17,20)- Group combat. Two years plus and still going strong, due to group dynamics and tank progression. *Elite Dangerous (PVE, PVP, MP- 1,3,4,5(maybe),7,8,9,11,14,15,16,17, 21)- Game has potential, having a galaxy to explore is great, but a couple months in and struggling with staying engaged. Trading is boring, dog fighting is fun, but against AI is getting repetitive. Currently not party friendly, no territorial acquisition, like Eve Online. I note that almost all of the games that attract me rely on violence. Currently I'm playing 3 of the above games WoW, WoT, ED, and although Elite Damgerous has a bunch of numbers associated with it, as far as keeping me engaged, it's struggling. 2/25/15 Updated post to include "static" vs "dynamic" labels.