Not possible to remove mandatory system fields?

Not possible to remove mandatory system fields?

Is there no way to make things like under Calls "Call Duration" or "Call Start Time" or under Potentials "Close Date" not mandatory?  These fields are useless for my organization and waste time but the box is grayed out to not make them mandatory.  It's just a bit frustrating since for Close Date for example we just have to pick whatever random date we feel like when making potentials...