A properly cooked egg would almost make a Big Mac edible. Though I don't know if I've ever eaten a Big Mac. When I'm forced to eat at Maccas (travelling to the parents when my kids were younger), I usually eat whatever special they have. But a steak sandwich with an egg is definitely something I will eat.
As to beetroot, it is common here for salads and burgers, but people either love it or hate it. I know some people who like it, but don't eat it much because if you drop some one a white shirt, you may as well buy a new shirt. They aren't picked, just cooked and canned. The can I have shows the ingredients as beetroot, water and a little sugar.
http://www.goldencircle.com.au/Produ...liced-Beetroot is what I am talking about.
As to pickled anything on a burger, no thanks.