Since I am the only team member in my role and the business is quite young, there wasn't much in the way of documentation or process when I started for my department, so it was very much a 'learn as you go' process. It was a challenge, but for some this may not be ideal.
The client facing role I have obviously can have its bad moments - clients can be unpredictable, and the job involves working around a to-do list which is constantly changing as new issues/tasks come in. Sometimes it does involve working with clients who can be easily frustrated, but to be honest this doesn't happen often.
The workload can shift often as the amount of tasks goes up and down depending on how many new clients come in with issues/questions within a certain time period. This can mean very long, quiet periods, followed by a very stressful week/fortnight getting deadlines or client expectations met; that's why it's so important that the team is supportive and we keep a chilled atmosphere! We do also deal with clients around the world, so sometimes working late for a 30 minute meeting in the evening is necessary.