TLDR; We have a tendency to interpret new evidence as confirmation of our existing beliefs.
Setting out to disprove one's own beliefs doesn't come naturally. We have a very strong tendency to only see evidence that confirms our preconceived notions. Watch this video and see how well you do.
How did you do? Even knowing beforehand that it's a psychological experiment, it can be tough to actively try to disprove yourself.
As a truth seeker, it's important to know this tendency in yourself, and seek to overcome it. Make a game of trying to find information that's contrary to what you expected. Remember that if you're willing to change your mind, you don't have to be wrong forever!