Hmmm, interesting question. I have had too many bikes to remember, but I can't recall a bad one really. They all had their own good and bad points, depending on what i wanted at the time. For example, my vn1500 was awesome for cruising and posing, but shit on fuel economy or off roading lol, my crf250l is a cracking little green laner but is unstable on motorways at over 80, my fazers were brilliant all rounders but slow compared to my gixer11, my cx500 rat was brilliant for rallies and dumping overnight infields ccar parks etc but didnt handle too well, rgv250 went like stink and handled like a dream but was a bit cramped..... the list goes on, all bikes have their own merits and limitations.
Even the little chinky 50cc scooter that was in the family for a good few years... it was slow, unstable, ugly, hard to start, fragile plastics and just generally shit, BUT .... it only used £1.30 of fuel a week to get me to work and back every day!!!! Tax was £15 and insurance was £60 fully comp.