Its tough to handle the success for Vidya Balan after hit film 'Parineeta'. She reveals, "When everyone says good things about you, you have to be careful that your feet remain on the ground. Acting is my passion it makes me happy. And I want to be just that - happy." Her brother-in-law is her biggest critic. "Though everyone has praised me for my performance in my first film, he told me that he thought I used my eyes too much," she adds.