I was planning a trip to Cricklewood using the TfL Journey Planner, as you do, when the predictive text kicked in.
And this happened.
First destination Cricklewood, as expected.
But in second place Criccieth, a small town in North Wales.
That's very odd, I thought. Criccieth's far beyond Zone 9, way off the Oyster map, indeed 200 miles distant.
So I humoured the Journey Planner, selected a trip to Criccieth and waited.
And the Journey Planner delivered.
Six hours, 53 minutes.
It kept quiet about the £85.20 off-peak fare.
But the route it came up with was perfectly valid, as were those for earlier and later journeys.
So I got cocky.
Let's see if it could do Criccieth to Lockerbie in Scotland.
How about Brighton to New Brighton.
It wasn't happy with Penzance to Wick, indeed even persuading it that Wick existed was tricky.
But Penzance to Thurso it dealt with, no trouble at all.
I checked, and it's not just parroting the Journey Planner on the National Rail website.
TfL are coming up with their own routes independently, or using some other engine to power their search.
I just don't know why.
It's useful for TfL's customers to be able to plan journeys between London and not too far away, say St Albans, Ipswich or Southampton.
It's quite useful to be told how to cross central London by tube to reach the right terminus for your onward journey.
But the ability to plan journeys between any two railway stations in the country on an in-house TfL website is... unusual.
Clever, but entirely superfluous.
Before you go thinking that TfL's web designers have the magic touch with National Rail services, there's another place where they absolutely haven't.
The Status updates page.
You likely visit the Status updates page to see if the tube, DLR or Overground are working, and to check future engineering works.
But you probably don't visit the National Rail tab, because the National Rail tab is rubbish.
When this version of the website launched, back in 2014, the National Rail tab had a message saying Status maps coming soon.
A status map would have been really useful, a snapshot of rail disruption across the capital - proper game-changing.
But the National Rail status map never came.
Last year they removed the 'coming soon' message and just left the list of rail companies.
And the list is also rubbish.
The list contains every rail franchise in the country, not just those that serve London.
Scotrail and the Island Line, which don't, are just as prominent as Southern and Southeastern which do.
And if disruption hits, the list offers minimal assistance.
'Severe delays' isn't a terribly useful message on a network stretching for hundreds of miles.
And the default 'Special service' status provides no useful information whatsoever.
Even if you think to click on 'Special service', no helpful summary of the issue appears.
Instead a link opens up for 'More information'...
...and that link goes not to the operator's website, but to nationalrail.co.uk.
Worse, it doesn't even go to the travel disruption page where you'd be able to find out more, just the homepage.
This is lazy linkage on a defeatist scale.
When looking forward, it's also potentially misleading.
Click on the tab for 'This weekend' and every rail service shows 'Good service'.
This is never the case, there is always engineering work somewhere, but the TfL website always says there isn't.
I even checked ahead to Christmas Day and was told 'Good service' on all lines.
So on one tab the TfL website can plan you a National Rail journey between Aviemore and Lowestoft.
And on another tab it can't tell you if the line to Alexandra Palace is closed.
These are peculiar priorities.