The game: DoW Soulstorm.
Match type: 2v2v2 annihilation between myself and a group of friends.
Okay, so me and my friend are playing as Chaos (myself) and Space Marines (my friend), we start building up a nice, sizeable force of infantry and tanks, capping every strategic point we come across, we had total relic control as well, so we were denying our friends their most powerful units. All was going well, we took out one team of Orks and Eldar with relative ease, stomping on any squishy units that got in our path.
All of a sudden, I notice that during our little rampage, one relic pops off the map, I think "Oh, no worries, it's just one relic, what can they do?"
At this point, we're heading back to our bases to reinforce and resupply, when out of nowhere a huge blob of red appears on the minimap, just underneath our wall of turrets, this is when I remember that the other two guys are playing as Tau and the Sisters of Battle, so whilst the Tau destroy my turret wall, what do I see other than LO AND BEHOLD! A Living Saint backed by the biggest swarm of friggin' infantry and the largest tank battalion I've ever bloody seen.
Then the Tau march in to accompany him, I think "Okay, we can do this, my marines are infil-" All my marines appear in full view, they have a detector, and with us being utterly unable to see it, we were at a disadvantage.
Whilst we dealt with the Sisters, our army and bases got hammered by long range fire from the Tau, at this point I open up the chat and simply type the following.
"I'll kill myself before I get myself beaten by wannabe Space Marines and squishy aliens." Then proceed to self destruct all my buildings, taking out a sizeable portion that were crowded around my Thermo-Plasma generator/Plasma generator batteries.
So I ragequit, but at least I took a chunk of their army with me.