It's mostly those that fly German ONLY and always outbalance the teams.
MkII Spit is a bit later version and it's slightly better than the available German planes. So this guys that are used to easilly get away from the earlier versions of the spit, without any kind of effort, get their panties in a bunch when they have to actually work hard for a kill, or even for survival.
"Grass is allways greener on the other side of the fence" type of atitude.