We get caught in slow traffic and start to cuss, in our mind first anyway. It's so easy to lose patience. Since we are not lord of the world, why should things always happen to please us? Even Christ encountered "inconveniences" so much worse than ours when he was on earth. We live in an imperfect world and what happens to us is permitted by God, not to screw us, but to make us more perfect. And this definitely makes patience a sign of holiness.