This article is from the Malinois Breed FAQ, by firstname.lastname@example.org (Nancy Bennett).
The Malinois is a "protection" breed -- it will defend its master and
its master's home. However, a well-bred, well-socialized, and
well-trained dog will calmly evaluate every situation and use good
judgment in responding. It should not be aggressive or nervous in its
attitude towards strange people or situations. Dogs with poor
temperaments or who have been poorly socialized or trained, however,
may be "shy-sharp" -- snapping or growling out of fear or aggression.
For this reason, it is important to buy your Malinois from a breeder
who produces dogs with good temperament and to get your puppy used to
meeting new people and dogs early in life, so that he will have a
relaxed and accepting attitude towards them when he grows up.