When you work as a ticket agent, the biggest portion of your job is customer service. Because of this, I don't think it matters whether you work in a small or large airport when it comes to the stress of this job.
Working with the public can be rewarding, and also very challenging, and this is certainly no exception when there are problems with their travel plans.
My daughter worked as a ticket agent at a major airport for five years. She had a couple years of college, but no other airline experience when she got a job there. She has moved up to other positions from there and really enjoys working at the airport.
Working as a ticket agent gave her a good understanding of how the whole process works. Now she doesn't have to deal directly with the public as often, but she understands the frustrations of being a ticket agent.