Employers hiring bank tellers are looking for candidates who can provide superb customer service regardless of stressful circumstances. Expect a lot of situational or role-play questions that will assess your ability to diffuse unsatisfied customers and handle money professionally. In addition, bank tellers must also be comfortable with counting and handling bills efficiently and accurately, so come prepared to answer a mental math counting teaser.
I can't remember exact questions but they ask a lot about the "customer experience". What your history is giving exceptional customer service.