For example, when i witnessed my mother tripping over a coat coming down the stairs and braking her big toe, when I saw a drunk elderly woman fall flat on her face entering the disco on Saturday night or when the blackboard fell on my teacher's head in Irish college. It also has been known to occur when you're in the middle of a serious conversation. You find it too amusing that all you can do is try your very best to concentrate on the seriousness of the conversation, but the harder you try the more you think "aagh i can't hold this in". Therefore resulting in a splutter of muffled sounds which frighten and disgust the person you are talking to in the first place! They can't understand how someone could be so rude but they don't understand that..that.. well that it's funny!
It is a strange feeling, this form of laughter, unlike the usual day to day laughing we usually do. This type comes gurgling up your throat causing your lips to start jiggling, if you're unable to control this sensation it results in an outburst of loud but silent cackling sounds. Almost similar to that of a dying asthmatic seal. Consider yourself lucky if you haven't added some snorting to that! The minute we let it out there is absolutely no stopping it until you suddenly realize that the person you witnessed falling may be hurt and you should try and at least pretend to be someway sympathetic towards the unlucky, injured person.
Why can't we stop it? Maybe it's in our nature? Or maybe there is evil in every single one of us, were we born evil? (wait, lets leave that conversation to Tuesday's Macbeth class!). I personally think it cannot be helped, I have tried my best to stop it but a secret giggle at someone else's sudden misfortune is a bit funny.. Hehe
Here are some painful (but hilarious) clips for you to watch (enjoy). Try your best not to laugh!!