Progressive rock has, arguably, always been concerned with trying to expand the possibilities for rock music, typically employing complex musical structures with the musician's aim to distant themselves from mainstream rock music. This has been criticised by some as an act of elitism. Many argue that this attitude removed progressive rock from rock's attempt to be politically engaged; as progressive rock typically focused on more idiosyncratic and esoteric lyrical commentaries. Further criticism contends that progressive rock's usual literary topics bared no relevance for many working-class citizens in England and as such, has customarily been written to and listened by the upper and middle classes.