Have an opinion about nothing…even though you have an opinion about EVERYTHING. Though I am one of the most opinionated people I know, I manage to have an opinion about very little when it comes to daily life. This is exaggerated when we are traveling. Where should we eat? I don't care. What should we do today? Whatever you want. I actually think that this is more related to my inability to make a decision about things than my lack of an opinion. Sure we passed 4,000 restaurants on our walk…but I definitely don't want to be responsible for figuring out which one we should eat dinner at.
Dub him the travel guide since he's been to all these places before (even if it was a long time ago). For our last trip, I told John he was the travel guide since he had been to most of the places we were going before (in college, 7 years ago). Then every time I saw something and asked "what's that?" he would say "I don't know" and I would proclaim that he was the worst travel guide ever.
Rely on him to be your translator even though he forgot to brush up on his German. This speaks for itself (oh, a pun!). I like to say that I now speak almost as much German from our five days in Vienna as John does…but that offends him so I won't say it…very often. Seriously though, German is a pretty easy language to pick up (especially when you have a translator who speaks the language at a kindergarten level).
Don't pay attention when he's trying to explain your route with the map and agree with his assessment of the situation even when you have no clue if he's right or not. Sometimes it takes me longer to figure out where we are on a map…I'm not a good map navigator…and often he was done explaining where we were going and how we were going to get there before I had even figured out where we were on the map. I'm much better at navigating by landmarks and retracing my steps. Fortunately we never got completely lost.
Insist on looking through your room one last time even though he claims that he has everything. On our trip last year, John left our power and plug adapters in our hotel room when we spent the night in Amsterdam on the first night of our trip. He claims I never asked if he had everything...I distincly remember asking (becasue I always ask). Ever since then I have not believed his claims of having all of our belongings before we leave a place. Needless to say he got annoyed with me constantly checking behind him.
Moral of this story...don't go on a long trip with someone unless you can bicker and still be friends in the end. We've managed to get through a big trip twice and we still like each other!