Kristen Stewart never thinks about how successful her movies are going to be when she signs up.

The 22-year-old actress - who has starred in one of the best-received movie franchises of all time as Bella Swan in the 'Twilight Saga' - no longer thinks about how her films affect people because she has to decide if she likes them first of all.

She said: ''I couldn't imagine doing a project with the idea of how it's going to affect people. It really has to affect you first, and if it does, then maybe it will affect other people ... I think that people who don't have that are clearly choosing things to become famous actresses.

''They're clearly choosing things to make money. I mean, I love Los Angeles - I love living here. But I wish that we could make things without the need to hit a home run every single time.''

Kristen - who is dating her 'Twilight Saga' co-star Robert Pattinson - admits she feels very grateful to have experience so much success in her shirt career and she realises she is privileged to have worked with so many talented actors.

Kristen - who stars in new movie 'Snow White and the Huntsman' with Charlize Theron and Chris Hemsworth - said: ''I feel so extremely successful - and not just because I can greenlight a movie now. It's because I've really only worked with people that I truly love.

However, she admits she has not always had good experiences on-set.

She told Interview Magazine: ''I've only had bad experiences with one or two directors. I think it always boils down to people not being there for the right reasons, and not being there for the same reasons. It's a miracle when things come together. But sometimes it just doesn't happen - and when it doesn't happen, you still have to finish the movie.''