I went to a pretty rubbish state secondary school, rated as 'needs improvement'. There were fights, alcohol and drug use on school premises, teenage pregnancy, etc. There was barely any school trips, months where we would have no teacher and would have a substitute who wouldn't teach us, barely any science experiments, PE was poorly taught, not many extracurriculars, etc. I do think the experience made me more well-rounded though, and I find it easy to get along with people from a range of backgrounds and feel more grounded because of it.
I work in a very middle class company, and I'm pretty sure all of my colleagues are privately educated, Oxbridge types. I've been told I'm well spoken, so I completely go under the radar as someone who lives in a council house and whose entire childhood was funded by benefits. I find my colleagues quite difficult to get along with if I'm honest. Seemingly innocuous small talk is from a point of view and experience very different from mine, with the presumption that I'm 'one of them'. They are confident and articulate in a way that I'm not.
I think the thing that sums it up best for me is that every week the office kitchen is left in a complete mess for the cleaners to clean up. Multiple champagne bottles, hundreds of coffee cups and beer bottles etc just left out with no thought or consideration for who is cleaning up after them. My parents have been cleaners in offices before, and it's one of those things that just gets me when I see it to see the lack of thought.
In my previous company I worked with a lot more state-educated people and I find them a lot easier to get along with.