Social Rules

When I filled in a referral form for the local Integrated Autism Service (IAS) I was asked 'Do you have an example of an unspoken social rule that you have struggled with?'

I struggled to answer this question as I did not understand what was meant by an unspoken social rule.

Therefore if anyone can give me examples of an 'unspoken social rule' then it might help me understand what they are referring to ahead of my assessment.