We succumb to self-delusion and irrational thinking every day, and that is normal behavior. It is normal, because it is adaptive. That is to say, over millions of years humans have developed "dependable fallback positions" on how to act that may no longer serve a purpose in today's world. Indeed, our biases can be quite harmful, and hold back not only ourselves personally, but all of society.
However, modern psychology has developed tools to manage these biases, and David McRaney has done an admirable job of presenting these tools in his new book, You Are Now Less Dumb, which offers "concrete, counter-intuitive, and fascinating ways to become less dumb."