The term "you're crazy" is used to make the target feel like they are overreacting or making things up in their head. It's a tactic for making you question your own experiences and emotions.
The statement "I never said/did that" is meant to make you question your own recollection or interpretation of events. It's a tactic for shifting blame and making you feel responsible for their behavior.
The statement "you're too sensitive" is used to make you feel that your feelings are excessive or irrational. It's a tactic for downplaying your emotions and making you question the veracity of your own observations.
The statement "you're imagining things" is meant to make you question your own reality perception. This kind of thinking undermines your confidence in your own perceptions and experiences.
The statement "you're just being paranoid" is used to make you feel that your worries are unwarranted or illogical. It's an attempt to make you question your own ideas and emotions by ignoring them.
The expression "you're the only one who feels that way" is meant to make you feel alone and responsible for the situation. It's a technique for making you feel like your emotions and experiences don't matter.
To make you feel that your worries are unimportant or unworthy of attention, somebody may tell you, "You're making a big deal out of nothing." It's an attempt to make you discount your emotions and question their veracity.