The ripple effect

Few things are as contagious as a loud laugh.

Where: the London underground.
When: a boring afternoon on the way home from work.
Who: some strangers and I. And a very funny book.
What: a ripple of laughter propagates from my shaking shoulders and watering eyes to the neighbouring seats, edging towards the carriage door.
How: I read a passage that is at the same time witty and silly, and cannot stop myself from laughing out loud in public. The more I read, the more I laugh. I try to hide behind the book. The lady sitting in front of me starts laughing too. So does the couple on my right. And the one opposite. And the girl on my left. I look up and two rows of seats are now in stitches.

Awesome. It makes me smile every time I think about it.