This is the cost of being lazy and relying upon wishful thinking.
I stayed up last night so I started my day at noon today and was therefore in rush to the classes in the afternoon. When I went out I noticed that it was cloudy and looked like rain would be coming soon according to my not very long experience with the weather in DC. I thought I would need an umbrella, but I a) was reluctant to trouble going back to my room; b) didn't have enough time (instead of getting back for umbrella, I'd rather reserve a few minutes to get a coffee at starbucks before the class). I quickly found an excuse for myself. A classmate who's having the same evening class as me is driving and I could probably get a lift if it's raining after our class. I was happy with this and comfortably forgot the umbrella idea.
What happened after our evening class was my weather forecast turned out to be perfectly accurate. It was raining. Then I started to look for that driving guy and finally found him in library. Everything seemed to be in my plan until he said he would not leave in the next 3 or 4 hours as he needed to finish up his memo assignment...
So I ended up running into the rain, getting nicely wet while arriving at home.