In my opinion this exceptional MMORPG perfected the idea of a world-wide, co-operative, PvE experience. It is because of this that the Guild Wars 2 community has become so friendly and accommodating, particularly for new players.
In PvE, helping another player is almost always worth your while as without a strong group of fighters you will be unable to kill the toughest bosses which net the best loot. The game rewards your co-operation, during the various community events, with an individual loot sharing system that gives all players a reward based on how much they helped during the fight. This means that everyone gets something, not just the one guy who delivered the killing blow to the boss or mini boss. New players and veterans end up fighting together with very few whining and moaning if certain people play badly.
You can also find a huge number of character build guides online, where GW2 gamers attempt to help others out with their ideas of where to allocate skill points, the best weapons and armour and which skills to use. If you join a guild, your guildmates will always be keen to help you level up, provide you with some equipment, crafting items, trade commodities or even just a friendly monetary donation.
It is always awesome and gratifying to play with a bunch of random people to take down a champion boss and I have rarely seen anyone be attacked for making a mistake. The community is half of the reason why I am still playing the game today.