As humans, we interact with people all the time. During this interactions, we estimate their frame of mind and readjust our speech and actions to best accommodate these social encounters. In a way, we constantly endeavor to get inside others' heads and interpret their actions and words and react accordingly.
Therefore, this idea of trying to figure out what another person was thinking is not uncommon. However, we are not always successful. In fact, we sometimes fail outright. For example, no matter how hard I try, I am still puzzled why "English (Pirate)" is listed as an alternative language on facebook.
What were they thinking? I may never know.
P.S. I now know what you are thinking though...