Although I was present at the big, open-air Mass at Bellahouston Park in Glasgow on Thursday, where the Pope got a rapturous reception from the crowds, it was not until I was watching the TV coverage later that I realised something quite significant about how this visit was going to be received by the rest of the country.
The build-up had not been encouraging. Weeks of negative headlines about the Church, about the disappointing take-up of tickets and the organisation and cost of the visit had started to wear down Catholic enthusiasm.
Just days before the Pope's arrival, Channel 4 chose to devote an hour of screen time to a documentary on Benedict's papacy by gay rights campaigner, Peter Tatchell, entitled, The Trouble with the Pope. The day before he arrived, news bulletins announced that a letter to the Guardian opposing the state visit had been signed by 55 writers, academics, politicians and other prominent public figures.
Many Catholics were bewildered, downhearted and wondered what kind of welcome the Pope could expect.
But there was a clue in the list of signatories to that letter that I failed to spot until I was watching the BBC news report of the Bellahouston Mass, and saw the camera pan across the huge crowd and rest for a few moments on the figure of Alex Salmond, the Scottish First Minister, in the front row, joining in the singing of 'Be thou my vision' with head back, mouth wide open.
Now Salmond is not a Catholic, and by his own admission not a regular churchgoer, but here was a man not only glad to welcome the Pope and associate himself with his visit, but delighting in the honour the Pope was doing Scotland, and clearly enjoying himself, too.
Every Scot I have spoken to since then noticed that same shot, and there has been much comment about the reasons for Salmond's enthusiasm, including the obvious one that he is a shrewd politician who wants to win Catholic votes. But even if this were just a cynical calculation, it would still be telling us something.
If there are more votes in welcoming the Pope than in opposing him — if backing the Pope is a vote-winner — then what does that tell us about what ordinary Scots, or ordinary Brits, think of the Holy Father?
It was then that I checked the list of signatories to the much-vaunted letter to the Guardian. Out