In the last couple of weeks I've had members of my team (all under 30, two of the four under 20) making snide comments to and arguing with each other, then in the last couple of days I've had to do their Annual Performance Reviews, which they've used to complain about each other, including attendance (one turning up at 7:32 for a 7:30 start nearly every morning), another unwilling to help a colleague "because I don't like her", etc., etc.