Boo!

Humans tend to be afraid of people who are different. As an asthmatic kid who got teased, and as a teacher working with kids, I've seen that happen many times. And it still happens with adults. Grown-ups usually don't tease people who make them uncomfortable, but they may avoid them and show by their body language that they consider people with disabilities or from another culture a little bit  - well, scary. But we can treat people who are different just like we treat everyone else. 

Being different isn't contagious, but being friendly is.