Could it be he was just interested in the places you had been to? I can imagine him back in the staff room saying 'had a World Traveller at the desk earlier, you should have seen all the visas' :)

totally assumed the same - just the curiosity (nosiness). Maybe he was hoping to see stamps from other places that he didn’t know. I’m impressed about the full page visa - any chance you wrote a trip report? That would be very interesting to read.

It happens. Visas attract attention (like you said, full page visa, definitely different from the other pages). Usually the border patrol people are more interested in "unfriendly" or "not so neutral" visas. No direct commentary, but might ask you a few more questions.

In my previous passport, (non-US) I had 114 border crossing stamps and 16 full-page visas from Japan, China, Indonesia, Vietnam, Brazil, etc.
It did cause some spark of curiosity with bored border crossing agents.

It would depend on relations between the country you're entering and what's in your passport. For example, in the current climate, most middle easter countries, Russia and China would be on the suspect list if you're going into the US. North Korea too. Many of the border guards are trained to recognise suspicious stamps) aka unfriendly countries.

Interestingly to OP's experience, my Georgian passport control experiences didn't involve going through each page with a hologram but did involve a bunch of waiting where I'm assuming they were waiting on a result from their computer. Arrival felt like forever (it wasn't but was longer than folks in other lines of other non-US nationalities) and departure was shorter but still involved waiting. I am assuming they are waiting on a result from a background check or something.

In Armenia, the arrival officer flipped through every page but he seemed pretty jovial about the whole thing.

They were waiting to get back the results from the backend of their database. That seems to be the case in Kazakhstan, Armenia, Russia, Belarus, Azerbaijan and other countries that share their databases with Russia. I don't think Georgia is in that group, but they have some sort of a backend process.

They were probably waiting for the results to come back while they were flipping through the pages to pass the time.
Until recently, border control agents in Armenia were Russian.
https://eurasianet.org/russian-borde...erevan-airport

In 1999 my friend and I were on the Tehran-Moscow 'express' (five days - and not possible anymore in a direct line at the time anyway. At some point we entered Dagestan and some soldiers enter the train (not sure to this day whether they were Russian, Ukrainian or Dagestani). My friend (Danish) hands over his tattered passport and as he does this the cover just detaches itself, so he's just sitting there holding the pages. We got taken off the train at the next stop and put in separate rooms, each with a German shepherd just outside. They grilled us for an hour or so. They were particulary interested in our invitation letter to Russia, which had been signed by the director of the World Bank in Moscow (my friend's father). They must have wondered what 2 rough-looking backpackers in their 20s were doing in that part of the world with a letter from the WB!

In Vietnam recently I had a border person want the boarding pass of the leg i just arrived on. Who bother's to keep that safe?

I had that happen in Lima, Peru. Fortunately, I was still able to pull up the mobile boarding pass on the AA app. Since then, I always make to to take a screenshot of it.

Any int'l flight I have a paper BP and frequently have it slipped into the passport as I hand it to the officer.

Actually, that's a pretty common request in SE Asia. Not a bad idea to keep your boarding pass until you're out of the airport.

Mine was right next door in Bahrain.

That also took approximately 30 minutes — they took my passport into an office around the corner before finally returning it to me — and I still do no’t know why.

More details about my experience are in this article at my weblog...

Not a US citizen, and only have a couple of interesting encounters. One of which was in JFK.

First one was when I arrived in Harare, and handed over the passport to the immigration officer. He quickly flicked through the passport, then threw it back at me with the comment “there’s a page missing”. And then it dawned on me that I’d forgotten to do what by boss had told me: Fold a 20 EUR note and stick it in the passport. I quickly retrieved the note, tucked it in the passport and handed it back. Immigration officer duly stamped it and welcomed me to Zimbabwe.

Second time was in JFK, autumn of 2005, and that was a much harder ordeal. I used to travel extensively in the middle east, and had multiple stamps from all over the place - including Israel. When I arrived at Ben Gurion the passport officer asked if I’d like the stamp on a separate piece of paper. “No thanks, just stamp it" I said, knowing there was little chance I’d ever go to Iran, Sudan, Yemen or Saudi, and therefore an Israeli stamp would have no consequences.

Passport officers in e.g. Abu Dhabi, Dubai and Bahrain either hadn’t noticed the stamp or couldn’t care less.

However, in the spring of 2005 I was operating a charter flight to RUH carrying money. Literally tons of Saudi rials, and as we’re sat there waiting for the aircraft to be emptied, two immigration officers comes to the aircraft asking for, well, passport. Slight panic ensues, as both the FO and I had Israeli stamps in our passports, and that’s a bit of an issue in KSA. The officers potter off with our passports, only to return 10 minutes later handing them back without a word. I opened mine, and saw that on one page I had the Ben Gurion entry/exit stamps, and on the reverse side were King Khalid entry/exit stamps, with the Saudi ones being dated some 3 months after the Israeli ones.

Fast forward a few months, and I find myself being sent off to JFK on business. After standing in line for an hour or two, finally made my way to the immigration officer who scans the stamps when his eyes suddenly lights up. He grabs a phone, and then next thing I know I’m in the interrogation room getting a right good grilling. They simply could not comprehend, and for good reason, how I could have Saudi entry/exit stamps dated after Israeli ditto. Took me an hour or so to explain what I did for a living, answering every question of “why did you go to XXX” with “because the company I’m working for sent me there”.

They eventually let me in.

PS
That passport is now used for training of check-in staff at a very large international ground handling provider. It’s always picked out as being falsified by the trainees, as it’s “impossible” to have a Saudi stamp dated after an Israeli stamp.

I don't think that Israel has stamped passports for years - they just hand you a stamped paper to slip in your passport. (How long ago did this happen?)