OK, not the worst ever, but the one which is currently annoying me: screw-top beer bottles. You know the ones, which look like traditional crown caps but actually screw off.
You can see why someone thought they were a good innovation; they look the same (which is important, because what kind of girlie-man drinks beer from bottles with the same type of closure as a bottle of coke?) while being more convenient: no need for a bottle-opener. But ‘looks like a crown cap’ translates as ‘authentic serrated metal edge’. They’re like little blunt circular saws. If a piece of packaging is painful to open, there’s something wrong with it. Come on people, this isn’t fucking rocket science. I’m looking at you, Fentiman’s Ginger Beer.