Distraction is when you’re doing something that’s not the most important thing to be doing. It is evil and should be avoided at all costs.
Interruption should identified as such, and embraced. It’s when things don’t go according to plan (they never will). It’s when the unexpected happens (it always will). It’s when you took the wrong trade-offs or made the wrong set of assumptions. It’s when technology shifts from under you and you need to learn something new or change careers.
What’s fundamental here is that interruption is so consistent as to be the norm. We should not be upset by interruptions, they are life. Moreover, they are the signal that things are unfolding as they should. Therefore, if there are no interruptions and things are going according to plan, then you should be anxious and frantically searching for what you’ve missed.