The propensity to hug varies enormously across countries but not always in the way one could expect. It is easy to associate hugs with open and extroverted cultures such as the mediterranean ones.
British people differ a lot from french people when it comes to greetings. For instance when entering a room filled with friends and acquaintances a young french student would kiss the girls on the cheek and shake the boys hands, although this suffers many exceptions: sometimes boys don't bother shaking hands or the whole kissing stage can be skipped altogether if there are too many people to greet.
A british student does not make body contact with his peers at all, he says "hiya" and that is about it for both genders. This lack of physical contact can be more depressing than the poor weather for people used to daily contacts.
The interesting thing is that for the french youth this kissing behaviour is the only kind of intimate body contact friends can have. The case of couples is a bit different as they can indulge themselves in full french kisses and hugs but these would not be ok in any public places.
In Britain on the other hand, if strong ties of friendship exist then people do hug more often, either to greet each other (females mainly) or to say goodbye (be it for the day or the whole month/semester/year/decade) or simply to express affection and support. This must be a kind of compensation for the total lack of contact in the early social life.
To someone who never experienced hugs before this experience came as a revelation. Here you do not need to be in a relationship to show your human feelings and give and receive this warmth and affection, this primal energy that must come from way back in time.
This is one of the things I miss most from the United Kingdom.