Pros
-- Constant interaction with customers (as a Teller) means you will definitely hone your communications/interpersonal relations and customer service experience. The first rule you're taught in training is "Say Yes", meaning doing whatever it takes (within reason) to accomodate the customer. If you absolutely cannot do what they want (if, for example, it would violate a bank policy or regulation), employees are encouraged to escalate the issue to a supervisor so that the customer understands WHY we can't do something (i.e. don't just say "It's not our policy") and also try to find a way to help the customer avoid the problem in the future. -- Learning that there are no "stupid questions": Retail banking has been one of the most tightly regulated industries ever since the Great Depression, and sometimes certain rules don't seem to make sense even to employees. Asking questions of managers (like, "Why is this type of transaction processed differently from that kind?") is a good way to build knowledge of the industry that can also come in useful in answering customers' questions. -- Schedules for Tellers are usually flexible, so you'll meet a lot of people from many different backgrounds.
Cons
-- At the time I worked there, the company was going through the transition from Commerce Bank to TD Bank. It was rather chaotic, because upper management was trying to integrate two banks with different policies, operating procedures, and information technology. As a result, policies on various situations could change frequently (and occasionally change back if things weren't working). It was frustrating to not have a satisfactory answer for customers who asked, "Why did they change that? I've been doing this way for years." when some new policy came down from headquarters. -- A lot of things that had been popular (and free) started to get charged for, which irritated customers. I think especially of the very popular coin counting service that now has a 6% surcharge for non-account holders.