To avoid letting down your friends, you are obligated to play when you don't want to.
"You're encouraged to log in everyday to help defeat the Doomsday Machine; it can make you feel guilty to forget."
"I have to sign into my guild every day or I can get kicked. This is subjective depending on how serious your guild is though."
"There are multiplayer guilds that get you ingame rewards for playing alongside, and those rewards almost equal real world money powerups."
"Only within my guild. It doesn't necessarily involve much teamwork, but I do feel compelled to log in and do the daily things for the sake of my guild."
"The base game does not have this, but there are all kinds of challenges that require heavy-lifting players who are almost constantly active to complete the challenge."
"Guilds are have dailies that give rewards depending on how much was donated that day."
"Contested territory is an optional times events where players have limited plays for the mode each day and must work together. Unused plays can be used by anyone on the team though."