The best game i ever played was a very small-hell grindy-ultra p2w title named Tales of Pirates distributed by IGG. This was like....ehrr... 8-9 years ago(?) if i'm not mistaken lol.
The game was not this big title, and as i said was super grindy. Also IGG is a greedy company and i remember myself spending hundreds of cash on it, but thinking back i had so much fun on that game that i don't regret any penny spent. And this because i had fun. Lots of friends, practically i never did anything alone on that game and was very challenging. There were extremely hard dungeons to do, guild wars to battle, open and instanced pvp, and even if the highest lvl when i left was 90 and took me 2 years to reach to it (LOL yeah ahaha!! ), well i never found another game to give me so much fun and satisfactions as that little game did. I was totally hooked, i could stay awake nights without sleeping, days without eating just to don't go away from pc. I remember having gaming sessions of 3 days long not shutting down the pc and checking often because there were portals that were opening only for short time just only certain days and we were entire guilds fighting to get possession on those portals. We were not using voice chat, screw that lol...we were having fun chatting on game when needed and how many times we were dieing because of this reason, was funnier. Ahhh i have so pleasant memories thinking back to that game.
After that, the only game that gave me something similar was City of Heroes, but not as much fun as ToP did. I think i will never find anything that can even came close to the experience i had back then.
Atm i went back to TERA and even if i do like alot the game and sometimes i play with my sister, well...is not that fun as it could and should be. This because of the community i guess. I have hard time to make friends for some strange reason and the guilds are not as they were once on the older games, nothing is as it used to be years ago and i feel like the good old times of the mmorpgs as i knew them has come to an end for me.