You shouldn't pace because it makes other people nervous.
James is trying to concentrate on a difficult programming problem in his open-plan office.
James wants to pace because it helps him concentrate.
James takes his laptop outside and paces along the back of the building where no one can see him.
James starts walking back and forth in the open walkspace in the middle of the office.
Both James and his coworkers are fully able to concentrate on their work.
Several of James' colleagues say that he's distracting them, but James ignores them.