When a teacher says "well done Donnie, good work" with great pleasure, that pleasure is a simulation (aka lie). Simulating affect is an effective and common method of teaching.
Simulating affect perfectly would involve a whole lot of different modifications to behaviour. For example, to simulate happiness you need to smile, crinkle eyes, add a lilt to the voice, not make abrupt movements, be relaxed, assume an easy posture, and so on.
A person who pays most attention to unusual features might be fooled simply by an exagerated smile. A person who does not pay more attention to unusual features would not be so fooled. They might not even recognize a big smile as an attempt to fool them.
Sally and Anne are bloody puppets. They don't have minds. D'uh.