Socialising is all about having an interest in other people, making friends, playing, sharing and helping.
My brother likes to be by himself a lot of the time. Sometimes this is because he finds it a lot easier. What people say and the games we play can be very confusing and frustrating for him.
There are lots of things that make being around people hard for him. My brother doesn't see the importance of being polite, like saying 'please' for example. A lot of people think he is being rude but he doesn't understand that people find this very important.
So, the last main area that people with autism struggle with is called imagination.