A meta riddle for?

Edit: this riddle is intended to be spoken, not read. There are no word clues.

"Wherefore came this plank?" asked Dr. Watson.
"We must first determine the exact whereabouts of it's origin." replied Sherlock Holmes.
"Well, just a moment ago I sat here, minding my manners staring out the window, when I felt drowsy and nearly fell asleep. I awoke quickly as my head began to topple over, feeling as if I was missing something and that is when I saw this flat piece of wood upon the floor where none was before." said Watson, scratching his head.
"What were you doing staring out the window?" inquired Holmes.
"Oh, I really don't recall. I had finished my tea and have no other duties this day therefore I was staring out the window."
"Hmm..." pondered Holmes. "Were you dreaming?"
"I don't recall..."
"Thinking?"
"Not sure..."
"Waiting for me!"
"Yes, yes, perhaps..." Watson said flustered. "I don't think I had a plan at all."
"What you have here is a fantastic case of an ineptitude to comprehend modern metaphors. Abire in animo." replied Holmes stoically pointing his pipe at the deceptive lumber. "We must get you a new hobby".

What is Holmes (and this riddle) referring to?

• Watson is as thick as two short planks clearly – Beastly Gerbil May 9 '17 at 15:16
• Note that "wherefore" doesn't mean "where", but actually means something closer to "why". – GentlePurpleRain May 9 '17 at 15:41
• @gentlepurplerain thanks for clarifying! I adjusted the wording. – abbaf33f May 9 '17 at 15:50
• Is the answer that he got board... bored*? I hope that's not the intended punswer... answer* – Piotr Pytlik May 9 '17 at 15:52
• As long as we're correcting words and whatnot, "it's" as in "it's origin" should be "its" because "it's" is short for "it is" or "it has" and is not a possessive form. – tilper May 10 '17 at 15:34

I deduce the answer comes from a combination of:

abire in animo - Latin roughly for out of the mind

and

"Wherefore came this plank?" and "...I saw this flat piece of wood on the floor where none was before." as well as the reference to deceptive lumber which points to a play on words for board / bored.

which would point to Dr. Watson having a case of:

being "Bored out of his mind".

• rot13: Gur dhrfgvba "Jurersber pnzr guvf cynax?" naq gur urnq gbccyvat "srryvat nf vs V jnf zvffvat fbzrguvat" vf n qverpg nyyhfvba gb n "obneq bhg bs uvf zvaq". Guvf vf yrff chmmyr naq zber cha, naq gung'f abg n tbbq guvat. – Rubio May 11 '17 at 21:03
• rot13: Fubhyq V abg unir tvira na nafjre gura? – ben-Nabiy Derush May 12 '17 at 3:34
• Why would you think that? Supplement yours if you like, but it seems fitting in its essentials – Rubio May 12 '17 at 4:00
• I am sorry, I must have misunderstood your comment. I will edit my post to give more clarity on my answer. – ben-Nabiy Derush May 12 '17 at 4:44