Contagion did a fabulous job of interweaving multiple stories from varying perspectives to paint a whole picture of the crisis, representing the human experience and scientific process simultaneously. Emotionally, the experience was sort of like this:
Contagion and I had a "you had me at hello" sort of courtship, I was so deeply impressed by this billboard concept.
It is a bit confusing, however, that the billboard is a giant petri dish full of bacteria, while the disease in the movie is a virus. But I'll let that slide.
Contagion wasn't just about a new, very deadly virus. A great deal of the movie explored the human experience of a global health crisis, with all the very realistic facets of it: World Health Organization and Center for Disease Control and Prevention workers risking their lives to cure and control the disease, people who hope to profit from the situation, and crowds who become rabid animals from crippling fear and uncertainty. Truly, I'm far more worried about people's reactions to a future pandemic than the disease agent itself.
So when the world seems to be ending, please remember that it probably won't, so you mustn't do anything you'll regret later when the world returns to normal. Spare yourself that awkward apology.