More cringe than pretentious, but boy from college was on a student exchange for a year to the US and returned with a strong American accent. The first time he called to speak to me at home, one of my parents answered and told me there was a young American man wanting to speak to me.
He was exclaimed surprise that I had friends who lived in terraced houses, 'so small,' apparently.
Another friend I was travelling by car with, to her home where we were staying, apologised that we now had to pass the outskirts of the 'industrial estate' she meant council estate but couldn't bring herself to say it.
Another friend used to complain and wish 'common' people weren't allowed into various shops we visited. I asked her how she thought they might police that and she seemed a bit put out.
An overheard one. Child was telling his mother, after being asked, that they'd had fish fingers for lunch at school. The mother kept attempting to correct that they must have been fish goujons, with the boy equally protesting, and louder, that they were fishfingers. She then stopped.
Lots more, but mostly pretentious people thinking they're impressing (they're not) by hinting, or plain boasting about money and status. One person I know went to ballet school nearly 40 years ago, didn't go on to have a career in that field but manages to shoe horn it into most conversations in an attempt to impress.