A shared trip reveals who believes inconvenience should be divided and who believes it should be absorbed.

Travelling together shows you how someone handles friction. Some people split every inconvenience carefully, some absorb it silently, some assume it will be absorbed for them, and none of this is visible until a train is missed. A trip is a compressed course in how a person deals with cost.

Watch for it, and notice your own pattern too. If you are always the absorber, it will not be noticed unless you say something, and resentment builds fastest in exactly this position. Agreeing at the start on how you will handle the inevitable problems is unromantic and it prevents most of what goes wrong between people on holiday.