Some people like to provoke strong reactions in others. They seek the fight, they care to win, they tend to protect, defend, and argue.
Some people prefer not to be noticed by others. They shy away, they let go, they hide and accept.
With the former, you have to be careful not to be drawn into the pit. With the latter, you have to be careful to assign the merit and avoid being forceful.
Mediation is always the best way, but you first need to figure out who you are dealing with.