Co-op games fren end up fighting each other because :

1) Friend join with low MF
2) Friend clear speed too slow, slowing down farm speed
3) Friend gameplay not pro, hit goblin when fighting elites Isnt that what you supposed to do...see goblin...fark the rest....KILL the green monster.....!!!!!!

@gladfly

u friend DH 200DPS meh?
u friend CRIT BARB 720KDPS meh?
ur other friend already clear other mob meh?

think 1st before hitting that farking goblin