The scaffolding you leave at home
Everyday behaviour is held up by a lot of invisible structure. You know the route. You know what things cost. You know who to ask. You know the social rules, and crucially you know the people who would notice if you broke them. Travel strips out all of that in a single afternoon.
What is left is a person operating with unfamiliar rules, no reputational stake, degraded sleep and a compressed timetable. Any one of those on its own is manageable. Together they reliably produce decisions people would not recognise as their own a week later.
Anonymity does a lot of the work
Nobody in this airport knows you. Nobody in this queue will see you again. The quiet social pressure that stops you from pushing in, raising your voice or ignoring a sign is largely built on the expectation of being known, and it thins out dramatically among strangers you will never meet twice.
This is the mechanism behind most of what gets filmed and put online: the tourist standing on a fragile monument, the passenger reclining into someone's knees and refusing to discuss it, the group treating a residential street at 2am as a venue. Very few of those people behave that way at home, because at home there are consequences that outlast the moment.
Tiredness is underrated as an explanation
A large share of bad travel behaviour is simply people who have been awake for twenty hours. Sleep deprivation reduces patience, narrows attention and makes small obstacles feel like deliberate obstruction. The person shouting at a gate agent at 6am is often not an aggressive person; they are a tired person whose capacity for handling one more problem ran out earlier than they realised.
This is worth knowing about yourself rather than only about other people. If you have taken a red-eye, you are not operating at full capacity, and the sensible move is to reduce the number of decisions you have to make rather than to trust your judgement in the ones you do.
The sunk cost of an expensive trip
Holidays carry an expectation of enjoyment that ordinary weeks do not. People have saved for this, booked time off, told colleagues about it. When something goes wrong, the reaction is disproportionate not because the problem is large but because the trip was supposed to be perfect and now visibly is not.
The same pressure drives the itinerary problem: cramming so much into a day that the day becomes miserable, then pressing on anyway because the tickets are paid for. A great deal of holiday misery is people refusing to abandon a plan that has stopped working.
Rule ambiguity gives people permission
At home you know which rules are enforced and which are decorative. Abroad you do not, and the honest human response to an unclear rule is to assume it is the flexible kind. Add a language barrier and the assumption gets stronger. This is why visitors do things at a heritage site or on a transport network that locals would never attempt: not defiance, just a genuine misreading of how serious the sign is.
The corollary is useful. If you are unsure whether a rule is real, assume it is. The cost of unnecessary compliance is almost always trivial and the cost of getting it wrong occasionally is not.
How to keep your own judgement intact
The practical fixes are unglamorous. Decide the difficult things before you are tired, which means booking the arrival transport, the first night's accommodation and the route from the airport while you are still at home and thinking clearly. Build slack into the schedule so that one delay does not cascade into a day of frustration. Eat and sleep on something resembling a normal rhythm on the first day. And plan fewer things than you want to.
When something does go wrong, the most reliable move is to slow down rather than escalate. Almost every situation that ends badly at an airport or on a street corner involved someone making a fast decision while tired and annoyed. The people who have the best trips are not luckier; they have simply removed more of the moments where a bad decision was available to them.
And a small note on the other side of the glass
Drivers, cabin crew, gate agents and hotel staff absorb this behaviour daily and mostly with more grace than they are given credit for. They are not the authors of the rule you have run into, and treating them as an obstacle rather than a person is both unpleasant and counterproductive, because discretion, where it exists at all, is extended to people who are civil about asking.