LPT: Keep an extra set of clothes in your car for the unpredictable.

I work with kids, so I keep a bag of extra clothes in my trunk for "emergencies." The other day, it was down pouring when I got to work. Even with a rain jacket and umbrella, my clothes still got completely soaked. If I hadn't had extra, dry clothes to change into, I would have had an absolutely miserable day in wet jeans.