I have had numerous big bikes but the Harley Davidson Road King Classic has to be the worst I've owned. I shipped it to my gaff in Spain but found it hardwork in and out the small villages with their tight turns. I ordered it whilst over in afghanistan and sold it in less than a year. Now my "provincial" runaround bike is a triumph retro bobber which is cool, so y, and awesome to look at and ride. I use a large 1050 GT for the inter country trips.
Worst bike, for me, was the Yamaha FZ750 - but that's because the 2 big accidents I've had have both been on those bikes (2 different ones). That said, I loved it .. It's all horses for courses I guess though - you wouldn't buy a Sports bike to go off roading (well, you might, but I'm sure it'd be discouraged). Harleys are built for American highways, lots of straight lines - I guess they didn't have Spanish villages in mind..
My worst bike was a Yamaha XVS650. The seat gave me a backache after 20 miles, the wind blew straight up my trouser legs due to the cruiser style footrests and because of the raked forks I had to pull it round corners rather than just lean and let the bike do the work. The chrome was also appalling and looked as though it would fall of at the hint of a good wash down. It's a shame as the first big bike I bought back in 1976 was a Yamaha XS2 650 which was my favourite bike ever.
Hayabusa, only because it was the most difficult to get on with of the bikes I've had, loved the speed, but not great when having to move it a round. I have a rocket now, and although its significantly heaver its much easier to live with.
The worst bike I have had has to be a Harris Suzuki GT550 the only thing it did good was to look good nuff said Saying that the Kawasaki ZX10R I had was a nightmare for reliability
i had a 125 mz it was a bugger to start and if it cut out i'd be there for a long time kicking it over trying to start it,turned out to be a lose points plate
My worst bike was a cx500, that was only because it was top heavy and I'm only 5ft 3in so I dropped it a few times......I ended up swapping it with a mate for an xs250, great little run around but had an oil leak lol.......my mate stripped the cx down and said I was lucky because whoever had it before me had problems with the forks and rather than fix them had packed them out with cardboard!!! I'd ridden from Isle of Wight to Leicestershire on it and had done over 100mph a few times