I have never had much faith in acquaintances one acquires by virtue of being close to someone else – a best friend's siblings, or a mate's relatives or colleagues. Very often such people tend to erode rather than strengthen the roots of a relationship.
No matter how nice one is to them, they usually are so diverse from you in values and attitudes that they keep misconstruing your actions, and passing off conjecture as fact. And often, they don't even realise the significance of what they say or how something could erode a relationship that two people have taken such trouble to build up.
