While there is plenty of idiot motorcyclists, there is also a never ending supply of idiot drivers. It seems like it's getting worse too. But the way I look at it is this...you're more than likely to survive an accident in a car than a motorcycle. Even if the car driver should be paying extra attention to any motorcyclist that may be around him, the motorcyclist should be taking extra percautions because assuming the car driver is actually paying attention is stupid...
Regardless, screwing around or not, it's tough to lose a friend. I am sorry for your loss.