The first one was ruined for me by the guy getting infected by the drop of blood falling into his eye while he looked up.
That one thing is just soooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo stupid I couldn't stand the rest of the movie.
The director mentioned not liking that part in one of the bonus features. In fact, they had another ending originally but canned it because that part would have made it impossible to believe (in the context of a world infested by rage-infected people, of course).