Since consumers feel that time is becoming an increasingly scarcer resource, service organizations are also becoming increasingly sensitive to the economical and psychological costs which they impose on their clients in waiting lines. Reports a study aimed at examining the relations between two variables which are controllable by banks (i.e. service interruption and clients′ participation in the service process) upon the perceived time spent in waiting lines, clients′ mood and perceived service quality. Results show that individuals who find the waiting time “unacceptable” have a very significantly lower mood and perceived the service as being of lower quality. Concludes that perceived waiting time can be modified through managerially controllable variables which also influence strategically important variables such as client mood and perceived service quality.