Confirmation bias is the tendency for people to find information that supports their beliefs and refuse to look for further information when their belief has already been supported.
For Example:
When someone is insecure, they will pick out information that supports their insecurity. They will be sensitive to people ignoring them and will constantly monitor whether or not somebody likes them.
While picking up on certain information may support the view, confirmation bias presents a skewed view of the world that is most likely not true.
Another Example:
Think about how divided people are online politically. Do people search for information supporting their counterparts? Not at all! People will only search for information that supports their view towards their political party (yes this is a generalization).