Putting fingers on the glass (EFIS, TCAS, Stormscope, Radar, FMS). Come on, it leaves prints.

Leaving the stormscope in the menu mode. It doesn't do any good unless you press the 360/120 button.

Slow radio calls in busy airspace.

High time copilots who try to act like the PIC.

Advancing my powerlevers before I ask them to set power.

Refusing to hand fly the aircraft after 200ft on climb out and outside the FAF. What are they going to do when the AP fails and they have no feel for how the airplane handles?