Gaslighting works a lot better when you trust the person or entity gaslighting you. If you weren't paying close attention to something and someone you trust insists you're remembering or perceiving it incorrectly, It's easy to start doubting your own memory, judgment, or perception about that event or issue.

Once you know you're dealing with liar who's using psychological and emotional abuse to disorient and control you, this technique loses much of its power. Totalitarian governments and abusers still use it, but they have to back it up with force.