Dare To Ask Talk And News About Our Differences 
I have grown up with a brother who has learning disabilities and find it repulsive that you would ask such a question. Everybody has things that can be made fun of, and I can guarantee you will not tell me that you like it when others poke fun at you. Someone with a disability cannot control it and did nothing wrong to obtain such a challenge. Their lives are already difficult enough without people insulting them and putting them down because of their challenge.
It's like if you get a bad haircut: you hate your new haircut enough and don't need someone to come and tell you it looks horrible on top of that. Instead of helping people with challenges and having empathy, you hurt them to feel better about yourself. In the end you will not feel better about dissing others rather than helping them. Just because someone has a disability doesn't mean they don't have feelings, and I can bet you that most challenged people would rather not have that challenge. Don't be heartless and ignorant. Show compassion.