Frequently I will click a unit so I can use the keyboard arrows or the go-to command to give movement instructions to that unit. Sometimes, however, the unit will immediately move in some strange direction before I can give movement directions.

I assume that is caused by the mouse (possibly by an inadvertent double click, or by an unintended second click in a different location) giving a movement command, but I am not sure because I never intentionally use the mouse to direct the movement of a unit. My wish is for a user option to disable directional movement commands by the mouse. It would be better to enable the user to avoid simple errors, than to insist that the user do things perfectly.
BTW, sometimes I want to direct a unit to move from its current location to a new location by way of a mid point that I select. The computer often chooses a route that is not where I want the unit to travel. Does anyone know how to tell the unit to move through one or more specific points on the way to its destination? Thanks!