lag(g)spike
When your computer is so slow it feels like it's doing push-ups in a slow motion movie. Then it freezes like a stupid fish out of water and suddenly everything goes nuts or just dies.
My WoW character was walking for 10 minutes and then teleported to the other side of the map.
I was fighting a boss and it took 3 minutes for my sword to swing.
I logged in and my character was still loading from last week.