Agree with you about the British public, what a bunch of *****!
As for the rubbish, that doesn't surprise me. The sheer scale of waste at Glastonbury and other commercial festivals is quite breathtakingly phenomenal. Brand new tents and quilts that have been bought for the weekend are just left discarded. And yeah, it's not uncommon to find a tent that's been used as a carsey, you learn quickly to look inside before picking it up to chuck in the back of the dustcart!
Do find lots of alcohol though! It's the only time of the year that I have enough bottles of spirits to have a 'drinks cabinet'. Last summer I found enough alcohol to last me right through autumn and into winter! Cannot understand why people would just discard (sometimes unopened) bottles of booze.
All very different from when we put on a festival or party. At the end of those there is no mess and no alcohol leftover! When we do a party we're clean and tidy, and we like to get proper pissed!