I would say:
- Slow acceleration (within reason)
- Poor reliability
- Expensive repairs
- Deteriorating bodies
Nowadays deteriorating bodies and slow acceleration are much a thing of the past.
IMO reliability and expensive repairs have taken the lead.
Some people buy expensive cars because they think expensive equates to quality. It's really wrong. Any car no matter how much it costs is covered by a warranty. Once that warranty runs out (say in 3 - 5 yrs) and your $50k car is now worth $25k, and the tranny / counter balance (look up Volvo V8) is shot - the dealer wants between $5k - $15k for a fix.
Same for reliability. As the cars become more and more electronic - the reliabilty goes down - especially when a 'problem' develops.
After owning two Volvos - one that had problems - they call the factory - because the tech's don't have enough info!