[vr]

Being prepared for an interruption does not mean paying attention to your surroundings or actively seeking distraction (e.g. checking email). The problem here is that even if you've made an attempt to block everything out but have not prepared yourself for an interruption, it still may happen and will severely hurt your productivity when you try to return to what you were doing. Keeping even very informal todo lists (e.g. comments in code, todo.txt) helps greatly when you need to quickly restore your context. Even if an interruption does not happen they give you a sense of direction and you can also use them to prepare future contexts for exploring ideas you came up with while working on the current task.