If you are in a body of water, and literally allow yourself to 'go with the flow,' then you let yourself be carried along by the tide or current without resisting or trying to change direction. This idiom, therefore, is used to express conforming to or going along with the wishes or actions of others. Its use can be positive or negative. In a positive sense, to 'go with the flow' shows an ability to both work with others within a group, and adapt easily to a given situation. In a negative sense, doing so can show a lack of character and resolve, especially with regards to giving in to group pressure or taking the easy option. As the video shows, this expression is common in both a social and professional context, and is similar to the phrases 'follow the crowd,' and 'take things as they come.'