Piddling v. Diddling. Here's where I come down on both. Piddling somehow is more positive. Even though there's not a lot of activity taking place, lots is going on in the brain of the "piddler". They are day dreaming as they piddle, and that's good for the body, mind, and soul. You can piddle anywhere, indoors or out and it requires no tools. As long as it's not a permanent condition, it's all good.
Now diddling is a different story. To me, it's more of a procrastination tool--a dressed up attempt to avoid something specific. Diddling is more about moving papers around on your desk, acting like you are doing something, so you don't have to do that which you are putting off, and would rather eat a worm rather than actually do. See what I mean?? Diddling is bad news. Don't go there. There's lots of denial going on in the Diddler and people don't come out of denial until they want to.
Piddlers can drive you crazy but they are actually harmless. Off in their heads, they have no reference for time. Where they are, there is no time. Piddlers cross the line, though, when they go to their "zone" and stay there. For non piddlers, there is no hell greater than that. Short of a cattle prod or a taser, you might as well just go on about your way and leave them alone. You are not going to change a Piddler. Ditto on the Diddler.
Piddlers make me laugh--Diddlers make me mad. Beware the Diddler.
And that's just how I see it.