Traveling is a real relationship test. They say you should never contemplate marrying someone until you've been on a trip involving a rented car and a folding map.

Fortunately my wife and i have very similar travel styles (though I did run that test to be sure, on a winter week in the English countryside, before proposing). But I have traveled with friends and relations and found our differing styles to be a major source of stress.

In airports and hotels and such I know the systems, I know what works, I know how to move quickly... and I don't really like it when my companions don't. (I think it is a major warning sign if, on a trip, you find yourself more and more aware of time spent waiting for your companion to pull themselves together -- because they're late for commitments, they're dawdling over trivial things, they insisted on checking bags while you never do, etc.)

On the other side of the coin I like to relax at my destination, make few plans, eat simple food in pubs and bistros.. and when my companion behaves differently that's really bothersome.

A few years ago I drove a new Volvo from Gothenburg back to the UK with my English cousin with whom I'd been very close and friendly. The driving and navigating went fine. But the evenings in Copenhagen and Amsterdam revealed him to be a terrible, incorrigible fussbudget about "foreign" hotels and restaurants; we'd take hours deciding where to eat, then he'd send the food back and complain bitterly, etc.

And on the money front I only ever keep vague track of who spent what, though I make sure I don't owe anybody much of anything... so I was really nonplussed, at the end of the trip, to see he'd kept a secret, precise ledger of every Euro/cent spent, down to every last bridge toll, ferry fare, sidewalk beer, or candy bar purchased at autobahn rest areas... pronounced that he owed me two pounds, 38p... and counted it out and handed it over gravely. I just found that weird. Seeing that control-freak side of him for the first time cooled our relations a fair bit.