we read/see/hear what we want to based on our assumptions and expectations. this leads to missunderstandings and often we are nowhere close to what's being said (written or happening). the assumptions affecting our perceptions can be images we have made up in our heads, expectations which we hold close to us, etc.
when something sounds egregious or obvious, or you think you understood it in the first attempt, just stop for a moment and read it again and again, ask the other to repeat it, or clear your eyes and see it again. and then confirm whether you are biased to preceive that or is it really there. then you would be in a situation to make an informed decision.
also sometimes the infomration might be incomplete or tampered with, so always factor in that possibility and confirm things without reaching any conclusions.