"You're too sensitive." Using this expression belittles and disregards the other person's feelings. It has the potential to make one doubt the veracity of their own feelings and responses.
"You're imagining things." To undermine the other person's faith in their own judgment and sense of reality, gaslighters may utilize this expression.
"You're overreacting." Saying someone is overreacting has the same effect as claiming sensitivity: it makes them doubt the appropriateness of their reaction and invalidates their emotions.
"I never said/did that." Gaslighters can make their victims question their sanity and recall by denying saying or doing things that they obviously did.
"You're just trying to create drama." It becomes difficult for the victim to voice valid concerns without worrying about being characterized as manipulative when someone is accused of dramatizing the situation.
"You're making things up for attention." The speaker's integrity and motivations are called into question by this statement, leading them to doubt the authenticity of their experiences and emotions.