I was terrible at PE, but in the last couple of years those who weren't taking it as a GCSE just got to kick a football around while the teachers dealt with those who were serious about it. Pretty good deal, so I can't really complain.
I guess my worst subject apart from that was Technology. Specifically, I took Electronics - a massive waste of time (bearing in mind that this was 1998-99), something I'll never have any cause to use, which took place in a class full of idiots with soldering irons who took great pleasure in melting loads of solder into big balls and throwing it around the classroom.
Yup, that was pretty poor and my grade reflected it - final project (burglar alarm for a jewellery box, or some such crap) didn't work, associated paperwork was absolute drivel, final grade E.