Strictly, my kit is the worst car I've ever owned; had a few breakdowns, stuff fallen off, leaks, noisy, uncomfortable etc. Unfortunately, complaining to the manufacturer hasn't helped
Otherwise, I've been lucky to never have a bad car IMO; slow (most of them), dull (Honda Stream), ugly (old Hyundai Santa Fe) but never bad. I've normally avoided the main manufacturers (Ford, Vauxhall, Citroen, Peugot etc) and mostly had Japanese, which may be the secret...