I've not looked into them intentionally using psychology to addict people as long as possible. I'm sure it's in there. I think that in the beginning days that this addction factor wasn't intentional, it just kind of worked out that way. There's nothing particularly interesting about standing in a virtual field and killing tigers for 4 hours in a row but the dopamine rush of going up a level, when it takes so damn long to make that happen, was pretty fantastic.

I too almost never played PvP but I did do the group raids and the people that actually were good would watch my back. I was probably more of a liability than anything else.