See @fredhincanada I'm trying LOL. For this one, I'll not only talk about the game I've spent the most time playing, but talk about the one that I spent a bunch of time playing (from alpha to beta to subscription to free-to-play before it's eventual demise) that I loved so much, a tattoo of it is on my left arm.
I've been playing World of Warcraft since an ex-GF got me into it back in Feb 2011 (my relationship with it is MUCH healthier and longer lasting than my relationship with her!), I have a tattoo of the Horde and Alliance crests mixed, along with the Rogue crest (my main since I made her in 2011) and the Forsaken crest (my main isn't that race, I just love their back story that much LOL), I haven't cancelled my subscription since I got it back in 2011 (although there have been times I've not played the game, whether due to life or not being interested in the expansion at the time), but like the saying goes: just when I thought I was out, they pulled me back in! I also play solo; while some of my toons may belong to a guild, it's never been anything I missed. I don't raid, I don't do PvP or Mythic Dungeons, I just love PvE (and currently enjoying the hell outta Delves) and the story. Have quite a few of the novels and lore books on my shelf. I even own a few of the RPG books from back in the day (when D&D 3E was out, if that tells you how old they are LOL). I can't honestly see a time where I'm not interested in or playing WoW (but as they say, never say never...)
But, the game that billed itself as a WoW killer (horrible idea to brand oneself as something that no other MMORPG has succeeded at, toppling the grandad of MMORPGs, but that's probably one of the reasons it failed), that holds such a place in my heart that I have the 2 factions' crests tattooed on me (and whose background has been my laptop background through multiple laptops), is Wildstar. Humor, an interesting story, great graphics and even better game play, the first time I saw the trailer I was hooked instantly. Still miss it to this day. I'll even drop a couple of their videos down below, to show you what it was like: