I have just received confirmation that I am, to some unknown degree, mentally retarded.
I woke up nice and early and got my things packed, breakfast in my belly and suitcase in storage well on time.
I left the hotel at a reasonable hour, thirty minutes earlier than necessary, in fact, and headed off to the Russell Square underground, from where I got to Piccadilly Circus without any trouble at all, until getting on the wrong Bakerloo line and ending up in Waterloo.

In my eyes, that's a fairly honest, London-fresher mistake.
Understandable. Forgivable.
And anyway, that is what I'd allowed my half hour of cock-up time for, a small, ten minute detour for mongs.

In my slight panic, I hurried to the Waterloo line rather than the return Bakerloo line and end up in Bank.
And then missed the train back to Waterloo.
I don't even know where Bank is.
...

I arrived at the Marylebone station twenty minutes late, having missed the direct train to Stratford-upon-Avon, I asked a transit officer if there was another way there, he told me to jump on the train at Platform 1 (and quickly, too, as it was nearly due to depart), and get off at a place that sounds like it's called "Lamington", delicious.
Leamington Spa, less delicious.
And here I am: on the wrong train, and going, as the transit officer put it, in the "general direction" of Stratford.