Trying to play with a friend on Warframe in the derelict, he would be disconnected several times while trying to host and insisted we keep trying when his internet was crapping out -.- So I would lose everything every time since I wasn't the host. This was when I was new to Warframe last year and it was hard to learn what to do in derelict with his internet problems. lol

Crashing or losing connection when you're about to win, obviously.
That's the worse that can happen... :x

Thanks for the giveaway. :)

It was when I got my first "rune" armour(which took me a few days of woodcutting to get) in runescape. I went into wilderness(an area where you can kill other players for their stuff) with it to try my luck on getting some items. After a few seconds in wilderness runescape crashed for me and I lost my rune armour. I was young back then so I nearly cried.

Like jbondguy007 said losing connection. (I especially had connection issues and was getting dc's every like 15 mins)

When u are grinding for like 8 hours for an item and someone else pick it before you (?) and later the items doesn't drop anymore D:

Losing glorenzelg from 25hc lich king in world of warcraft due to a DC and a rollback, yeay me o/

finding a brony on my team ;P

lol jk, worst is when theres either 3 or more ppl from another country who don't speak English -.-

Accidentally trashing my B-gear 86 e1'd engine (leveled down to 85 so I could use) in Ace Online. To explain, getting 1 of those things usually took about 4-5 months of grinding, and it was (at the time) the FASTEST engine you could get for BGs. Worse, it was a gift from my old Guild Leader. I miss going stupidly fast in that game, catching players unaware, and blowing up huge camps of gears. Never got lucky enough to get a 2nd one, sadly.

RNG was a right bitch in that game.

Nightmare-ish you say? Hmm... That would be when I (we) found out that when my roommate closes doors to his wardrobe my internet connection gets cut off. We keep the router in his wardrobe cuz the cable is inside. Since that day he makes fun of me when I play online. ;_;

11-2 playing Hearthstone...

Internet disconnects and I get eliminated :(

I never won so many matches again

getting packet lossess every 5 minutes..

Battlefield 4 lag when it first launched.

P.S. I live in SEA too but I don't play DOTA...

just after achieving 500 dota matches,i lost yesterday to easy bots.

Getting kicked out of matches because I was trying to get achievements

thanks

I never had a "nightmareish" experience. But the first time I played L4D Versus I was called a fail-tank. :< Kept me away from playing versus for a while

Playing Portal 2 co-op with a friend whose connection is unstable, resulting in either of those:
a/ Coming back to the menu of the game when disconnected (and have to restart again)
b/ Waiting for the player to come back, which takes about 5 minutes and happened at least 4 times in an hour