"That's how I feel when I'm feeling good."

An adult man with autism explains how he physically exhibited his happiness as a child. The whole video is good, but check out 2:00-5:15 to see how he and many other people with autism may show their feelings in ways that make sense to them but may not make sense to others. Watching that short section will help all the "normaltistics" understand others better.

http://autismawarenesspage.com/seeing-autism-through-adult-eyes/