Polite greeting or insult?

Today, at the supermarket checkout, the cashier said to me 'Hiya Hen'. I was a bit taken aback because people don't usually address me as 'Hen'.

It started me wondering how often I unwittingly offend or confuse people with my particular colloquialisms.

For ages I didn't realise that the people in my office had never heard the phrase 'Get In'. I use it all the time to mean 'nice one'. Unfortunately my colleagues were a bit confused, understanding it in a more sexual sense, consequently worrying about my seemingly perverted views on certain topics of discussion.