Most of us think of the internal dialogue, the voice in our head, as valid thinking. If you take a moment to really listen to what this voice is saying you will quickly notice it is mostly made up of negative, repetitive and destructive thoughts.
In other words, this voice is (mostly) bullshit. If we forget to separate ourselves from these thought patterns, they can dominate our mind. Sometimes you just need to ignore your problems and pretend they aren't real because at the end of the day, you probably made them up to begin with.