Telling children that they are 'cute'.
'Cute' is meaningless praise. What can a kid do with it? Try to be cute some more? Cute is only cute when it's unintentional. Forced 'cuteness' is horrible. And cute isn't a virtue anyway. The word can be used to mean naughty or pretty or charming or childishly amusing - none of which are particularly praiseworthy.
Cute is condescending. My dog is cute. Children are complex, wonderful, interesting little people with eternal souls and the potential for deep thoughts, powerful feelings, new ideas and brave and selfless acts.
Cute doesn't really cut it.
(But yes. I've called my kids 'cute' too.)