My younger sister is 24 and has always been quick to laugh at people falling over and hurting themselves etc, the thing is she takes it much further than most people and will actually be bent over in stitches whilst everyone else is doing what they can to help or just showing concern, an example of this happened last week at work when a woman hit her head on a shelf and almost knocked herself out, my sisters face turned bright red and she had to actually leave the room to avoid laughing at her in front of everyone
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At the moment I'm concerned at the way she is treating her fiance as I can see him walking out before long
, he is a pretty big bloke, not obese but overweight and she actually encouraged her kids to stick pillows up their sweaters and walk around immitating him, he ignored it the best he could but she was doubled over in stitches. She rips the mick out of his clothes and often wrecks his shoes and trainers because they ammuse her so much and she creases up if he hurts himself or if he gets a stomach ache. The kids are the same.
She just finds everything so funny, nothing is serious with her. 