I think a good travel partner packs the most important thing first, a sense of humor. Humor is needed because rarely do plans go as perfectly as expected, the unexpected happens. Humor makes the adjustment better.
A good companion is willing and able to stay on budget, regardless if the budget is high or low.
A good companion is considerate of time constraints and is punctual. They are able to use time wisely.
A good companion does not pack everything they own, knowing that added luggage is added burdens and often added fees..
A good companion has taken sometime prior to the trip to orient themselves to the destination. Knowledge is power and knowing in advance helps lessen disappointments of the highly anticipated.
A good companion is willing to try new experiences from food to cultural traditions.
A good companion is flexible and diverse. They are up for a variety of options from shopping to museums to religious icons to nature.
A good companion has energy to complete a full day of fun.
A good companion does not want to stay up late drinking all night and then sleep in the next day. They realize they can do that at home.
A good companion is patient. Everyone knows "a few minutes" in travel time could mean hours.
A good companion is a good communicator. They can listen but they can also seek information when necessary.
So are you a good travel companion?