Honestly the biggest eye opener with GW2 is how active the open world is, people don't just sit in cities, there is always a meta event happening somewhere on the map and people flock to them to get participation awards, that is usually tied to legendary/ascendant crafting.
It's like, having a FATE, that goes for ~30 minutes, taking you around the map and building up to a big event with a world boss at the end.
'Battle for Jade Sea' is the latest endgame meta event, and was honestly breathtaking with how the entire event takes place, with big groups of players setting up for the siege and getting all the preparations done in order to fight the final boss, in a big grand showdown.
Link to a video:
https://www.youtube.com/watch?v=MqJuYV6bz_M