Given most of our profession comes from a computer scientist background, it is expected that we use a scientific and verifiable approach in decision taking processes. Unfortunately, nothing could be further from the truth. Our environment is ridden with irrational convictions that come from out of nowhere. Those are of two different kinds: memes are "ideas, behaviors, or styles that spreads from person to person within our culture" while cargo culting is the "ritual inclusion of code or program structures that serve no real purpose". This talk will try to challenge some of those common ideas, by highlighting the most pervasive ones.