I never had a bike I hated, but I did have one I couldn't seem to ride. Back in the '90's I bought one of the last DT200 Yamaha enduro bikes, which had good power and seemed light enough for my purposes, and had a modern-spec chassis, unlike the KE and XL enduros I had ridden years before. I had a '92 YZ250 as a dirt-bike at the time and thought this would increase the opportunities to ride off-road, which it did, except that I fell off. A lot. Like just about every ride, and multiple friggin' times if I ventured beyond the shoulder of a paved road. It was sprung softly, and even at my weight, would tap easily, so I had the ride height set high at the back, and every time I found myself halfway up a goat trail and needing to turn around (because I coudn't continue UP) , I'd put my foot down on the high side, which would unload the suspension, at which point I'd overbalance and go down flailing and cursing with my head pointed back the way I'd come, my dick in the dirt, and a trailbike on top of me.
The pseudo knobbed tires weren't able to deal with anything softer than hard-packed gravel and this combined with the soft suspension meant I was always trying to do slowly what needed to be done with at least some momentum, and, though the get-offs were uniformly from 3mph or less, it was ego-deflating to come back with thigh bruises and a sore elbow from such a tiddler bike all the time, and after a month or so of this I sold it.