I'm generally a very very warm person but also direct and straight forward, so I've come across as rude and hot-cold when interacting with Brits and only really realised this at uni. Thing is, I don't mean to be rude at all nor offend anyone and sometimes I really find it hard to find the line on what would cross it because it's not something that in my experience has ever been seen as rude, but at uni I had many instances where it was pointed out.

Just to clarify I was brought up in NL and in the UK, in very multicultural ethnic enclaves where straight talk has never been an issue. I noticed at uni Hungarian and Greek students had the same issue and interacting with them was a lot easier.