The shit I've tasted is mostly Danish beers. There's a big warehouse here in Denmark called Bilka and their cheap beers are called "Pilsner special" or "Special Pilsner" and they're probably one of the worst beers I've tasted!
The Danish beer Tuborg is my favorite beer, but on the border between Denmark & Germany there's some shops were you can buy them in smaller bottles that we call "granat beer" and a Tuborg granat beer was probably THE worst beer I've tasted my entire life!!! I took one zip and I almost puked. I was semi-drunk at the moment, so I'm usually able to drink stuff that doesn't taste that good when I'm like that.
I've only tasted Heineken in a can when I was at Gran Canaria and I thought it was pretty good, but then again, beers are as much taste as music, films, food and so on.