Random question but why do middle class people pretend to be working class when there not

I know a few and it's really annoys me for some reason no idea why it greats on me either being from a middle class back ground myself but unedcuated so have to do a working class job when I do get back into one. Think id discribe myself as mudle class. I say be proud of your class and hertige why hide it out of fear or embrasment no matter what class you are and those who denigh there even is a class system are usually the ones who hate people for there class.