why can't i shut up

A work colleague was was talking about his girlfriend,I asked if he had a photo of her. He duly took out his phone to show me a photo of his girl.
I looked at the photo and asked "does she  have SPECIAL NEEDS" he wasn't happy.
I then went and said to other colleagues his girlfriend was fit,so much so that she had won silver at the special olympics,this comment went right around the factory in less than 2 minutes a new record.
I then thought about how cruel I was and appologised then blew it by saying "You know you have the last laugh as you are getting a fuck and a carers allowance.