I like effortlessly casual social interaction. I like multiplayer shooters where you share a few gaming moments with randomly selected players. I even like pugging in mmorpgs. Guilds are great but they do involve effort, effort in game and effort out of game (forums, administration and schedules).
I think one of the reasons I enjoyed LOTRO so much was that I had great experiences with pick up groups. Partly this was because the community was bit more mature than WOW and partly this was because the game did a great job of training people into grouping.
Of course the problem with pugs normally is that you never know who you are going to get and the performance of the group generally falls to the lowest common denominator. That is why PUG raids are generally destined to fail. Tobold's proposed system of institutionalised Pick up and put down guilds (henceforth to be known as PUPDoGs) might actually solve this problem. The entry requirements would ensure that only players ready for a given level of content would be in a given guild and the as the guilds only focus on one dungeon each they might be expected to develop an institutional memory of tactics for that dungeon.
Am I the only one who likes casual social interaction? I doubt it. The history of mmos shows that there are many different types of players with many different motivations: People who play multiplayer games solo, people who never join a guild, people who play a pvp game in PVE mode. I suspect there are quite a few folk out there who would enjoy an mmo more if the burden of social interaction was reduced rather than increased.