Emotional Inception, also known as Pathokinesis, is the power to manipulate emotions and feelings. This ability seems to work primarily by projecting one's own emotions onto another being, causing them to feel the same emotion.
The users of this ability are presumably able to project all types of emotions, including happiness, sadness, rage, fear, etc., causing short-term change in emotions. The exact length of this change in emotion is currently unknown.
Maggie Vera's powers expanded in "Don't Look Back in Anger", allowing her to cause other people to feel whatever emotions she does. In a heated confrontation with her father, she unwittingly sent out a large blast of energy which affected two guards, causing them to become enraged and fight each other. The guards fight each other so brutally that they are both shown laying on the ground, either dead or knocked out.
In "Unsafe Space", when Macy Vaughn and Maggie were stuck inside a tiny marble from the Command Center, Macy began freaking out. Maggie was able to consciously use her power to transfer a feeling of calmness into Macy, which allowed her to relax.
Later, Harry Greenwood asked Maggie if she could use her new power on him, presumably to not be in love with Macy anymore, so that his emotions will not interfere with his duty as a Whitelighter.
- Original Power