Sitting in 7D on a 737-900 once, right next to the mid cabin lav. Both parent of a baby got up to change a dirty diaper. The dad was inside the lav changing while the mom held the door wide open and watched. The smell was pretty bad. Everyone around was looking at each other and scrunching up their noses. I stepped up and spoke up, asking the mom if she wouldn't mind closing the lav door. She smiled sweetly and said "sorry" and closed the door to let dad finish the job.

Of course, we could have all just sat their and gagged and addressed the mom and dad on FlyerTalk.com.