An interactive stack is a software component which stores data in a last in / first out strategy. The regular behaviour of an interactive stack captures all input streams of push and pop commands which do not lead to a stack underflow. We investigate the behaviour of interactive stacks for input streams outside the service domain. We specify a fault sensitive stack, a fault tolerant stack, a robust stack, and a fault correcting stack. We subsequently implement them by state transition machines introducing a control state and a data state. Beyond the case study, we phrase general conditions and adequate notions for modelling partial services of interactive components.