The QTEs in RE4 during the unskipable story sequences with Krauser, where if you died you had to start it over, were a terrible idea. Thankfully, they split that part up into two segments. The MASH A NOT TO DIE DUE TO THIS GIANT BOULDER CRUSHING YOU bits were stupid though. Button mashsing is stupid.
The QTEs in Madworld during miniboss/boss fights were fine though. They're not necessary to kill the bosses, but when you do pull them off you deal a good amount of damage and you get a nice little gory sequence.