How shameless they are?

So I was travelling from Indore to Delhi, 3rd ac side lower seat. I was having confirmed ticket and was sleeping suddenly I felt someone pushing my leg and sat near my leg and when I asked why? He said he said please adjust for sometime. I thought he was having waiting ticket . But instead he wasn't even having general ticket. Why do they do this? I thought to complain to tt but humanity kicked in as he looked tired. I don't know why these guys travel without ticket and that too they step into ac coach