My teenager told me today that his cousin had said he must come to her sister's dinner party. I believed it was unlikely my niece would have put it that way, so I asked what exactly were her words.

Son: "Would you come to the party?"
Me: "But that is asking you, not telling you."
Son: "But I thought she meant she wanted me to come."
Me: "She might well like you to come, which could be why she was asking you. But I don't hear her telling you to come."

So much fiction is passed around in conversations, the senders telling what they believe to be true, the receivers believing what they think they are hearing, and all the while the real substance of the message is becoming tweaked, coloured and thereby lost in transmission. What originally stood up to rational inquiry rightly falls over later due to irrational embellishments, context gets changed, and what is heresay becomes honoured with the same credibility as eye-witness accounts.
The same goes for reading something that is written.
It is so much easier (and lazier) to "read into something" by neglecting to think rationally about what those words actually meant. A lot of personal "hidden agendas" sneak into the message that way.
My son clearly had one in the conversation quoted above, wanting to go to the party and thinking his cousin would have more sway with me than himself.
Sometimes these agendas are conscious, a deliberate dishonest manipulation of meaning, but more often than not they are simply bad habits of thinking that lead eventually to believing misinformation without even the awareness anymore to discern truth from falsehood.
Thereby we deceive ourselves and distort our own perceptions.

Are you sure what you have read is indeed what I wrote?
Are you sure what you have heard is indeed what I said?