I would fix other people's lines if they asked me on occasion. The hard part of writing is the architecture of it, getting the story and structuring it. Not the tweaking of lines.
“People have this belief that actors are able to go out there and say, 'Oh I choose this job,' but most of the time we're just taking the job we can get. We don't just get offered thousands of jobs; we might earn one job a year and that's the one we'll take because we've got to pay the rent.”