All three types of feelings can be contagious, and emotions don’t have to be grand and obvious to have an impact. Subtle displays of emotion, such as a quick frown, can have an effect as well, Barsade says. She offers this example: “Say your boss is generally in very good humor, but you see him one day at a meeting and his eyes flash at you. Even if they don’t glare at you for the rest of the meeting, his eyes have enunciated some valuable information that is going to have you concerned and worried and off center for the rest of the meeting.”