People misuse the overhead cabin by overpacking, stuffing oversized items, or using it for all their stuff.
Many first-time travelers have no idea about transit visa requirements or the repercussions of overstaying a visa.
Many people think travel documents are quick to get. While it may be true for some countries, most take at least a week.
Years ago, I got on a trans-Atlantic flight, and the dude beside me STANK—sour week-old BO. Since then, I have always had a tiny container of Vick’s Vape-O-Rub in my carry-on.
A lot of new travelers complain about how they don’t get the food they like or how foreign things are.
Lots of bags, oblivious about how much they’re blocking others with their stuff, whacking everyone in the shoulder with their purse or backpack as they board. Whew, I feel better now
Many people believe flights are always on time and make the mistake of not having enough time if they have connecting flights.
Pack very heavy! I saw many travelers with two heavy rolling suitcases struggling to walk in narrow streets in Italy (e.g., many steps on the Amalfi coast) and struggling to get in trains quickly.