We do not know if the bad will occur. We hang in uncertainty as we suspend between the good and the bad. This is anxiety, the fear of uncertainty. Some people would rather encounter the bad predicament rather than suspend in insecurity. Uncertainty to them is worse of all bad things that could possibly happen.
Security is the core value above all else.
Anxiety is a sin because it demonstrates a lack of confidence in the sovereignty of God to deal with our concerns. It is only after we tie ourselves in a knot that we realize apprehension is sin. It is a besetting sin to some Christians. It enfeebles the soul. It ruffles the temper.