The worst kind of liar is one who lies by omitting crucial information. Like if they say things like “I’m not seeing anyone else!” and accuse you of imagining things when the fact is that they’re not currently seeing anyone else but they were when you accused them of it. So they’re not technically lying but they’re just omitting the facts. So many other examples but you get the picture. They’re gaslighting experts because they make you question your sanity.