You can set a destination that requires lots of turns for your unit to reach. If you do that without enablin auto turn, the following turns the units move automatically only when you hit next turn. The keyboard tab in the options doesn't give you a shortkey that could allow you to move your unit.

And this is particulary annoying, since those units with destination set are displayed as having movement left on the empire tree. You can't force all movements to see which units are really idle without any order.