Anyone:

Laziness=You don't want to do a task, so you choose not to, and you're fine with that. You either dont care if it gets done or you figure someone else will do it.

Procrastination=You want to do the task, but you put it off because it seems difficult/boring/time consuming.

Executive dysfunction=You want to do the task, and intend to at that very moment. There is no significant reason not to, but you can't because your brain is having difficulty transitioning between activities.

The key difference, he points out, is that if you experience guilt or shame from not doing it, then it's NOT laziness, because those feelings indicate, on some level, a desire to complete the task.