What does Christianity say about dangerous risk taking behavior?

Sex first of is not a sin God wants us to be fruitful and multiply ,its just unwise to have children before being in a committed relationship hence premarital sex is a sin.Drugs are defined by humans not by God .As wearing a seat belt it may or not be safer to wear a seat belt ,Christians are also known to be sinners .We were never expected to be perfect and its wrong for you to h arras your friend and expect him to be perfect ,when His God doesnt even expect that of him.Just except him for who he is .