Those of you who saw the movie 'Due Date'... did you find some parts to be

[No regrets just love.]

really sad/serious? I started crying during the scene where they were in the public bathroom and Zach Galifianakis was acting out a 'scene' for Robert Downey Jr... and I almost cried when they were at Jamie Foxx's house and his dads ashes get knocked into the floor and he tried to get them off the floor..

Is this just dark humor that I didn't get, or did the writer purposely make it go from really funny to serious throughout the movie?