I'm going to second "it's just a game" or "real life comes first" or "I play for fun," when it's used in an inappropriate context. "Real life comes first" does not mean it's cool for you to stand up 24 people in your raid to watch a TV show. And if you play for fun, then don't play in a group environment where your "fun" playing impacts other people negatively and then use that statement as a way to justify it. And this being a game is not an acceptable reason for screwing over other people, or being a selfish, or acting like a jerk.
All of those statements are fine and true on their own, but they are very frequently used as excuses for circumstances and behaviour that are unjustified.