The oldest lie in the world is definitely this- soulmates exist. And love exists. Not the normal love, I meant the ‘soulmate’ love, where for one particular boy, there exists only one true love/girl, no one else will make him happy as much as she does. Romeo and Juliet, Heer and Ranjha, Mirza Sahibaan etc. They were just extremely attracted to each other and horny for each other. Thats it.
And also religion. There may be a creator of the world, but there is no jesus, allah, shiva, etc. These are just mythologies and its time we treat them as such.