Is it normal to laugh at these?

Is this scenario normal?
The class is history, the topic under scrutiny is foot binding. I picked up on the whole 'unable to walk properly and therefore can't run away' bit, and thought of hobbling. You, know, when the mine keepers punish bad workers by not killing them, but by hobbling them. The keepers put a block of wood between the ankles, then swing a hammer into the feet. The action causes the ankles to break, thus turning them into agonizing noodles of busted bone and flesh. The thing is, I started LAUGHING during my explanation. Not a small chuckle, but full out, holding my sides and laughing myself out of my seat.

The next day, we were talking about Seppuku, now that we finished talking in China. The Japanese way of suicide being honorable there, something to BRAG about, yet so frowned upon here in the western civilization... It cracked me up. I laughed, again, like I did when I tried explaining hobbling.

So, I ask, is this normal?