Mind has a tendency to construct a model of reality, which is largely just a crude representation of reality at it’s best. It’s this reality that we are all living in. We are living a lie narrated by our minds.
When mind gets confronted by something that threatens the reality, defense mechanisms kick in. First defense mechanism is denial. In fact for information we learn for the first time we outright dismiss, it has never happened to us before. Often to get even our attention, new things require repetition.
There are exception, in familiar and safe environments any changes in the environment gets right away our attention.
There seems to be a kind of filter of expectation. Our minds is at peace when everything goes as expected. Like a radio channel which plays the sort of music you are expecting. If something does not work as expected, your mind wakes up and starts to react.
We do not necessarily notice new elements in familiar kind of pop song only until much later on. This happens all the time. Our minds get enough of the familiar, so we do not even pay attention to the slight changes that have happened.
All this is natural and automatic. Consciously we can become aware and mindful about these and at key moments take a moment to consider what is going on. This is especially good practice when you notice defenses.
15 Common Defense Mechanisms is good place to start identifying which of these do you use most often and then to start practicing the more mature responses in situations.