Kalos had some strangely difficult trainer battles considering most bosses and rival fights were pathetically easy.
>the double Furfrou really early on
>the Axew with Dragon Rage, 2koing any non-Fairy you have at this point, appearing just after Connecting Cave
>basically every Fighting type user bar Korrina from Route 11 onwards since they all have tough Pokemon with coverage out of the ass, plus the one double battle with Machoke and Mr Mime
>that Sturdy Shell Smash Rock Wrecker Crustle, I lost a fucking Poliwrath to this from a crit in a nuzlocke
Most of these aren't tough in terms of wiping, but they're way tougher than the bosses. Korrina in particular is a joke with shit coverage, yet Battle Girls and Black Belts are formidable opponents that are deadlier than the Veterans. It makes no sense.