I think that your sister's brain assumed she couldn't make tea *and* respond coherently so soon after waking up.

Whereas I think your brain wanted more time to think quietly about the problem in the background, but wasn't willing to admit as such.

Unfortunately, I disagree with both of those things. My sister wasn't making tea: she was waiting for Dad to make it for her, which takes no brainpower at all. And I wanted coffee before I even started looking at the problem, so when I went to the kitchen I didn't yet have any facts in my head which I could usefully think about in the background...

Oh, ok :-)

Well, this isn't very helpful in terms of whys and wherefores and tautologies, but FWIW I do the same thing - it's not a peculiarity limited to the Tatham clan :)

Of course, it occurs to me, the fact that I do it rules out the possibility that it's about the smell of the drink :-)

Ooh, that's a good point, I suppose.

I mean, I do enjoy the smell of tea, and will make myself a choptliver-pint-mug-o'-tea for comfort/inspiration/moral support, when necessary, and will feel much better for the warmth and the smell and then end up not drinking all of it, but given that you are (obviously) completely unbothered by the smell: I posit that it's a Cultural Thing, old chap, and we're brought up with parents and family and family friends saying "ooh, let's have a cup of tea before dealing with that" or similar, so it becomes ingrained response to the point that people don't realise that they don't need the tea to make their brain work?

Thing. Sorry. Babbling. Excuse me while I rush off to a lesson...

:)

It's because internal "To Do:" lists are not parallelisable until you have had tea/coffee as applicable.

That leads to stalling when the first item on the list is "Obtain Tea/Coffee". Your sister of course realised that tea was incoming without any effort on her part. However, "Update internal To Do: list" was second on the list, and so she couldn't break free until the tea actually arrived.

Once you've had the first tea of the day, you can parallelise as necessary, and thus circumvent similar stalls for the rest of the day.

I am laughing because that is exactly how my brain works, and it breaks down in the same way at 4pm when my research group goes to tea.