One of the most cathartic things about going to the movies and also for those writing a screenplay is that we watch people get to things that we would love to do, if only we were just a little braver, smarter, stronger, etc. As a screenwriter ,, when you are writing a screenplay, it is your job to give the audience what they want by providing them with the opportunity to see your characters doing things that, frankly, regular people would never be OK with doing. Remember, your character is supposed to be a hero and, in order for that to be true, they have to be willing to demonstrate extreme commitment to achieving their goal, whatever that may be.
This may sound a bit too esoteric and like "film school" for some of you, so let me simplify it even further – a character is most compelling to watch when they have decided that they have their mindset on a goal and that nothing, and no one, is going to stop them from completing it. If your protagonist is a bank robber who needs to pull off this one last score so that his kid can desperately get the kidney transplant he needs and he can finally retire, you think he's going to let a little thing like the law, or a couple of cops, stop him? No! He's a hero – his job, his very function, is to overcome insurmountable odds.
One of the most common mistakes that rookie screenwriters make when writing a screenplay is giving their characters a visually compelling, conflict free line of work. This is a problem, because most adults spend a large portion of their free time at their jobs, meaning that, at some point, we're going to (most likely) have to see your character at work. If your character has a boring job, it is going to make the character themselves look boring, and your audience is going to stop caring, which is kiss of death for a screenplay and, by proxy, a film.
You want to, instead, give your character a profession that demonstrates the following qualities in spades:
– A large amount of obstacles for them to overcome – no one wants to watch a hero stuff boxes all day
– Any sort of regulatory system or government that makes things more complicated for the protagonist
– A ton of problems, in any form, no matter where they come from
– Lots and lots of visual conflict
– A high amount of emotional tension and high stakes
This does not necessarily have to be a legal job, nor does it mean the character needs to have to be directly compensated for it – in this case, a job has to do with responsibility, not the amount that the character is being paid for it. As long as it generates a palpable tension that the audience can get invested in, that's what important when you writing a screenplay.