In political science they sometimes study the difference between what people learn and what people remember, between what people know and what they think they know. In general, a lot of results show that people remember only the facts that support their position, and construct views around those "facts" they do know, or whatever information stuck with them best. This, by the way, is an argument AGAINST democracy - it is essentially impossible for people to be fully informed.
Anyways, the reason I bring this up is because I am a living example of how this happens. Not in politics, where I try to stay relatively well informed and keep an "open" mind when it comes to facts. BUT, I am a good example of this at work. Three times recently I have had one "fact" stick in my mind about a case and had it cause me to construct a reality about the case that simply was not supported by the totality of evidence. In all three of these cases there was some exam of the claimant that's report made me feel like the claimant's condition but surely be very severe and they would likely be allowances. In all three cases, when I went to meet with a DR about it, or sent it to be reviewed by a doctor, they asked "where is the evidence that they are telling the truth?" or, in one case "where is the evidence they have ANY medical condition?" I had completely neglected the fact that despite one exam where they were presenting as in pain/very psychologically distressed, there was no evidence of an ongoing issue or of it being severe as the claimant alleged. I had constructed a reality of the case around the idea that the claimant was suffering. Once the Drs pointed out my errors, thorough review of the evidence showed that in all three cases, everything besides the one "fact" I had picked out indicated the case was not that severe and that these people could work.
I feel like I need to step back, take a breath, and return to looking at the totality of the evidence.