Worst bike I ever had was my very first. It was a kind of hybrid C11G/C12. It was taller than me, had a kick like a demented mule, and I sold it to a guy in Jesus sandals...never saw it or him again.
Not much better was the foul little Bantam I learnt on...oiled up constantly...spitting little thing...
Best, of course, was my Baker TZ350 racing outfit...the most fun you can have with your clothes on...