Gaming the system
We start by considering metric 1 in the examples given before, which is related to the on-hold time of a call. There are several ways to avoid the penalty of crossing the threshold for this metric:
One such way is to drop the call (a technical error is always possible after all).
Another way is to have an automated answering machine ask the user some (possibly irrelevant) questions.
A third option is to answer the call but forward it to a different team as soon as the user starts explaining the question or problem. In none of these cases, the service can be called qualitative, but the appropriate metrics are perfect. Other metrics can be gamed in similar ways.
To make things worse: Since usually only a small amount of KPIs are selected for monitoring service quality, they are easy to keep an eye on and follow-up. It is thus possible to make sure most of the metrics are managed in such a way that success is guaranteed.