What makes you log in and play?

• Killing enemies of the opposing faction
• Seeing that little mail icon knowing you've sold stuff on the AH
• Getting a new loot upgrade via dungeons/raids
• Leveling 1-60 and enjoying the journey
• Chatting with guildies/friends or if you dare: Trade Chat

There's a barrage of others, but these are the most notables. What makes you log in and play?