There are lots of bikes over the years i just could not gel with, the 2 worst offenders where a recumbent that was a really good bike but i just could not feel safe on wile using near traffic as it was very low to the ground.
Second was a unicycle, that i really could not get on with, ever watch the stunts on utube etc they look great fun and so easy but for me it was nothing but pain and shame, must say that it was great to let some friends have a go at there own risk just a pity i had not recorded them i could have sent them in to a tv show for £250 a clip.