Impressions can be hysterical, but also demoralizing and rude. But what are impressions? At first they appear to be playful representations of other people. This is only half true. Yes, they are representations of a person, but they are also caricatures. Henri Bergson writes about caricatures in Laughter: an essay on the meaning of the comic. He says “There will always be… some favourite distortion towards which nature sees to be partially inclined. The art of the caricature consists in detecting this, at times, imperceptible tendency, and in rendering it visible to all eyes by magnifying it.”  Every person has some physical attribute that is defining about the way they look. A good impression highlights these attributes and in turn makes them comic.
In the case of Jim Carey’s impressions, rather than going after speech (a tendency for impressions) he creates visual caricatures with his face. In his bit he portrays people who have defining qualities in the way they look, such as Jack Nicholson, or James Dean. he then exaggerates those features to highlight the comic quality of natures own disposition and engages with audience without saying a word.
However, a caricature or impression can also go terribly wrong. Some people, such as Donald Trump, have tried to do impressions of disabled people in order to capture a crowds sympathy for themselves, but only causing the reverse to happen. Bergson writes “A deformity that may become comic is a deformity that a normally built person could successfully imitate.”  In the case of Donald Trump, when he did his impression of disabled reports it was not comic as the deformity of the reports are not one people could successfully imitate making his impression more of a mockery than anything else.
Impression and caricatures are a double edged sword that can highlight the comic in another person or the insensitivity in the performer.
 ibid. 23.