I once overheard two pregnant women argue over who should get the one remaining seat on a bus. They were near the front and I was at the back. I decided I'd intervene and offer my seat and the problem would be solved.
BOTH of them told me to mind my own business. I called them both cheeky fat bastards but seeing the look they gave me I got off at the next stop, at least 4-5 stops away from where I was going.