I swore I'd never get into an online/multiplayer component of games; the various offline difficulties of GoW kept me happy - ripping through the game on splitscreen with friends on Insane difficullty - I'd seen people waste their lives in Warcraft or Call of Duty blitzes.
Then somebody gave me a 6-month Xbox Live scratchcard.
That was the Beginning of the End.
Six months, and 15,000+ kills later, the "Seriously" achievement popped up - even though it should only take 10,000... I was a 0.1% ranked elite GoW player; I could take down an entire enemy team without aid, even predicting terrible online-lag, kids either side of the Atlantic craved for me to be in their online clan... But that achievement - as all achievements and trophies do - killed the game. So I never played it again.
Did I have fun? Yeah, I did. I can recall stories of online adventures, people I met. But I won't.
Was it worth the time to say I unlocked a single image - over tens of thousands of hours - just to put on my online profile? Hell, no.
Also - Unreal Engine crashes like a mofo on my workstation. Unity FTW.
EDIT: This does not include Gears of War: Ultimate Edition for Xbox One. WOW! Way to go to take a fairly good idea, fairly stable online component, and totally fuck it up. It's like reverse engineering the "polishing a turd" theory. Sure, it looks great, but GoW:UE is, without a shadow of a doubt, the WORST online multiplayer game in existence... Unless you like shooting enemies 6 times in the head, just to be shot once in return to be gibbed. There is a review for the movie "Monster Dog" in The Gore Score; it simply reads: 'sucks farts out of dead cats. FUCK IT!'
Same applies to GoW:UE.
Knowing they'll use the same netcode, which is blatant garbage, Gears of War 4 can fuck off. Just because it's 60FPS, and the devteam wring the fuck outta Substance Designer, it doesn't mean it is actually any good.