You could also face weird reading times, television show fanaticism early in the morning and anything else an imagination can conjure a friend doing in the privacy of her own home.

McDonald certainly was schooled the hard way.

"Lessons were learned, and if we ever did travel together again, I think we'd likely be much more upfront about our needs and goals for the trip," she says. "Also, I think having a little compassion goes a long way.

"People have different breaking points and comfort levels, and if you go into a new experience knowing that, I think it makes dealing with situations like these easier, or at least quicker."

Circumventing problems

How to prevent trouble before you take off? Psychologist Joseph Cilona weighs in:

Plan ahead. Before you ask your boss for days off work, much less make airline and hotel reservations, get together a few times to discuss a possible vacation together. Individuals should talk about needs, preferences and goals to gauge if they're compatible. Recognize that even the best of friends simply may not be good travel partners.

Negotiate conflicts. Negotiate possibilities to resolve conflicts — again, before any commitments or purchases are made. Remember that fair does not always mean equal. It really comes down to priorities and what's important to each person. Be sure that each person addresses the importance of the issue being negotiated.

Preplan timeouts. Discuss and agree on how conflicts will be handled before you leave on the trip. Also, create a specific plan to enact should things get heated during your trip. Use experiences from the past with each other to devise a strategy that will work for both of you — again based on being fair, if not equal.

— R.A.