Answer:emotional contagion
Explanation:Emotional contagion is the phenomenon in which a person's present emotion affect or triggers the same emotions from those around him or her .
Our emotions are able to pick up and be influenced by the emotions of those who are present with us at that moment , positive emotions are likely to trigger effective cooperation,reduce conflict and increase task performance.
Tiffany comes happy at work and she is able to perform her work perfectly such that her happy mood becomes contagious that even the customer walks out feeling happy.