You don't need to work in Central Casting to spot:
The Talker. The Crying Kid. The Possible Terrorist. The Couple Going to the Big Game. The Make-Out Artists. The Impatient Businessman. The Manure Salesman. The Accountant. The Hoodlum. The Lawyer. The Expectant Mother. The Tourist. The Cowboy. The Recluse. The Difficult Customer. The Road Warrior. The Beauty Queen. The Jock. The Brain Surgeon. The Marine.
Although often once you get to know them, The Manure Salesman turns out to be The Brain Surgeon, The Talker is The Accountant, and The Possible Terrorist is some guy going to Dallas for a job interview.
And don't think they're not casting you.