In the L4D2 demo, none of my friends were on Steam so I joined a random match.
Now, in the very first section before the safehouse I was totally raped and they all reached the safehouse before me. They'd all re-healed and picked up the next round of medkits and I didn't even get a look in (my health was in the red).
I must have asked for a medkit 4 times before I started swearing. Then I used caps (my mic broke a while ago) and nothing. In fact, they opened the door and went on their merry way.
Needless to say, I picked up a shotgun and went to town on the guy left in the safehouse with me. Someone ran back in to help him, and I took him out too although (from what I remember) he clipped me and I started bleeding out.
The guy outside had been left alone with the horde, and so ran back in to get us all up again. One of them had started a votekick but it wasn't finished by the time he got to us, so I shot him down too. And then I disconnected, with them all bleeding out in the safehouse.
Selfish pricks, I'm not even ashamed; I'm bloody proud.