The most embarrasing thing that can happen is to be surprised when you come to a turn that you weren't prepared for.
The phrase "what is it doing now?" comes to mind.
Brief and just go thorugh what you plan to do so that the guy besides you can be spared from any surprises such as "what the
are you doing?" or "where are you going?".
If you fly to the same place 3 times a day with the same guy, focus on the non standards. Look for CB's, small planes without mode C, fatigue, complacency or any other than normal master cautions
I fully agree with the KISS rule, but whenever I'm flying with someone I usually don't fly with, or have never flown with, I brief it in full, just to clear any questionmarks. It's a good indicator of the style in which you fly. After that first approach, both know what you aim for and how you like to execute your sectors. This helps as the day continues.
/LnS