People may act differently online than they do in person for a number of reasons, including:
Online disinhibition
The internet can lower inhibitions, which can lead to people behaving meaner or opening up more than they would in person. This phenomenon is sometimes called "toxic disinhibition" when it leads to hostile online environments.
Anonymity
People may feel more invincible online and say things they wouldn't say in person.
Lack of non-verbal communication
Body language, eye contact, speech tone, and language patterns can help us process information, but these are absent online.
Self-esteem
Psychologists say that only presenting our "best selves" online can negatively impact self-control.
Projection
People may make negative comments to project their insecurities or feelings onto others.
Social distance
Online interactions can lead to problems stemming from social distance.
Provocations
People may encounter more provocations online, such as political opinions they don't agree with or news that angers them