Does really the planets have any influence on individuals life ? How can one believe this theory?

The Modern science tell us that Sun & Moon combination causes some vacuum in the atmosphere which causes the low and high tide of the seas and ocean. The earth contains more than 70% water when the planetary influence can cause such a drastic change in the ocean, why it cannot make the same effect on human body? Your body too contains around 70% watery. Further more, the cosmic rays and radiation too are influencing ones thoughts, thinking and behavioral pattern. Hope this clarifies the doubt about planetary influences on the earth.