The Dunning-Kruger Effect is what causes people who suck at something to also suck at realizing how badly they suck. This is why total quacks like Steven Chase Brigham and Kermit Gosnell think that they're splendid, highly skilled and competent physicians.
Risk Compensation is why people will behave more recklessly the safer they believe they are. This is why distributing condoms does nothing to halt the spread of AIDS, and why giving out contraceptives hasn't done squat to prevent abortion -- because when people perceive sexual activity as risk-free, they engage in much more of it. See also Taking Chances: Abortion and the Decision not to Contracept, by Kristin Luker.