"At the end of every shift, we play a recording of the most outrageous call. We then give a rating on how the agent handled the call. It is a good way for all us to laugh, joke around a bit and many times learn new skills from that agent."
Becoming upset is OK, becoming angry is not. Be able to explain how you keep composed, understanding that in a TSS role that you are responsible for helping to solve customer's problems, you didn't create them. Being able to provide examples where a customer really got you upset, and how you dealt with it can be used here. Specific examples of how you diffused the tension, have any games you use in the team, tools that are used to 'lighten things up' would be good.
Most of us have something that we dislike about our job, and that's fine as long as we're willing to get the job done with a positive attitude. Pick something that you disliked about your past job that is not relevant to the role you're applying for. For example, if you worked at an internet cafe before, you might state that you were continually frustrated by the inconsistency in income especially when there were slow days in the shop. Despite that, share how you still kept a positive attitude at work and at the end of the day, you knew it was only a matter of time until you could move on to a better role. Reassuring the interviewer that you never let dislike get the best of you is key to landing the job! Interviewers enjoy hearing that you maintain a positive outlook despite difficult situations and that you'll get the job done despite there being areas that you do not enjoy.