The Oscar winner said that it's not necessarily about how large the movie production is or the size of her part, playing the right characters is what's important at this stage of her career.
Bullock said: "I don't care how big the role is. I don't want any more experiences that aren't amazing."
The 47-year-old, who has starred in Miss Congeniality and The Blind Side, emphasised that she has evolved as an actress.
"As I've gotten older, I say 'No' a lot more. I've become a better fighter for my work. I didn't have the guts to do that before."
Speaking about her part in Extremely Loud And Incredibly Close, Bullock explained how she was especially challenged in the role.
"I've played mothers often. A lot, actually. But this mother's very complex," the actress said. "She's in the process of grieving too, so she doesn't have much energy to fight for that connection she so desperately wants with him. She doesn't seem nurturing - or any of the things you would want a mother to be at the moment a child really needs her.
"That was hard, but also what I liked so much about it. It seemed more real. We've seen mums depicted in films - usually it's very squeaky and she takes care of everything, when in fact, life is messy and hard. That's what makes their relationship so powerful - it's not perfect."
Watch Sandra Bullock in the trailer for Extremely Loud and Incredibly Close below: