Being falsely accused is just one form of being delayed. The kind where it takes longer to clear it up.
> Your bags are misplaced or stolen.
Does worrying help with this? Does it make it less likely for it to happen?
> You can't take your water bottle so now you have to buy another for 10x the price.
Yes. That is how it is. Does worrying help with this?
> Your passport was accidentally torn so you now have to explain that to a skeptical border police officer.
Border guards see torn passports all the time.
> our flight is cancelled and you must now rush to the only hotel to book a room before they sell out
I don't know where you are flying where there is only one hotel. Is this a real worry or are we just catastrophising here?
I got plenty. My luggage got lost more than I can count. Missed connecting flights due to delays. Had a flight take of with four hour of delay to then ingest a bird in the engine on climbout so we had to land back imediately with a smoke filled cabin. Got selected for extra screening plenty of times, had been asked to go to the security office to answer extra questions about my luggage. Had my share of flight cancelations too. The most serious issue was perhaps when I got waylaid for a few weeks because an airline didn’t like the stamps on my imigration paperwork. According to my imigration lawyer the airline was in the wrong and misunderstanding the law, but what can you do? We got it sorted with the embassy as soon as we could and I was on my way.
Thing is that worrying would not have helped with any of these. Simply not the right answer.
AFAIK (because I do regularly) you can take a water bottle, you just have to fill it inside security which doesn't seem a great hardship.
This means that even as a passenger with a completely clean record, every action you take is viewed through the lens of being potentially suspicious. The worst case scenario is not being delayed - it's being falsely accused.
Less importantly but hugely more likely is that you travel is disrupted. Your bags are misplaced or stolen. You can't take your water bottle so now you have to buy another for 10x the price. Your passport was accidentally torn so you now have to explain that to a skeptical border police officer. You don't speak the foreign language well enough to explain yourself. Your flight is cancelled and you must now rush to the only hotel to book a room before they sell out - or risk waiting in order to convince the airline to book it for you.
I don't disagree with you that some relaxation can go a long way to making such an experience more pleasant, but it's still true that there's more to go wrong in one international journey than in a whole month of most people's day-to-day lives.