Worst coffee I've had has been out of a plunger - it seems whenever I see plunger coffee at someone's house, I think it will be a good idea (hey, it's got to be better than instant, right???) and ask for it. I then sit there and watch them pour the BOILING water over the coffee. At that point, I know I'm going to spend the next ten minutes trying to pretend I'm waiting for it to cool before deciding to take the plunge into the ashy goodness that is burnt coffee.