I'm a great one for using my common sense as to whether to eat something or not. I definitely don't don't worry about any best before/use by/sell by dates.
I agree there is way too much food wasted. I believe this is partly to do with the fact people expect shops to have everything at all hours whereas years ago if you went in a shop an hour before losing and they were out of a particular item you just bought a substitute, went without or popped back the next day.
As a youngster I remember going with my nan to visit her sister, my great aunt. She made us a sandwich from an uncut loaf, the first slice was covered in mould so this was cut off. I wasn't sick, nor did it put me off eating bread or food at her house. There was no fridge, meat was kept in a meat safe, she also had no running water.