Territories and zones,..

human intimate zones is normally entered by another person for one of two reasons
1. Intruder is a close relative or friends,...
2. Intruder is hostile and may be about to attack

while we will tolerate strangers moving within our personal and social zones, the intrusion of a stranger into our intimate zones causes physicological changes to take plave within our bodies.
the heart pumps faster,..adrenaline pours intot he bloodstream and clood is pumped to the brain and muscles as physical preparations for a possible fight or flight suitation.

This means that putting your arm in a frinedly way on or around someone you have must met may result in that person's feeling negative towards you, even though he or she may smile and appear to enjoy it so as not to offend you.

If you want people to feel comfortable in your company, the golden rule is to "keep your distance"
For example: a new employee may initially feel that the other staff members are cold towards him, buy they are only keeping him at the social zone distance,..until they know him better,.as he becomes better know to the other employees,..the territorial distance between him and them decreases until eventurally he is permitted to move within their personal zones ,....