Every time a user clicks on a row or a column in a visual, every other visual in the page feels an urge to refresh itself and respond to the click.
Visual that are based on direct query may issue multiple queries for each refresh.
Depending on the number of measures used in the visual, the number of generated queries can be as high as 10 or even more for a single visual.
Read on for more information and what you can do to avoid this problem.