Why would a player need to “drop a ball”?

Question

Why would a player need to “drop a ball”?

Answer 1

One reason would be an unplayable lie.  Like if your ball was right on the edge of a water hazard and the only way you could hit it was to stand in the water.  I have done this when the water is shallow enough.  Just took off my shoes & socks, waded in and took the shot.  But if the water is too deep you would have to take a drop.  

Another reason would be ground under repair.  Like if they were fixing a leaking water tap and the ground was extremely muddy.  You are not required to play of of unnatural hazards that are not actually a part of the course layout.

Still one more would be if you were up against a man made hazard such as a tool shed, drinking fountain, or a grandstand if you are in a tournament.

I am not sure, but you may get a free drop if your ball is lying on a paved golf cart path.  

All of these are free drops except possibly being forced to stand in the water.  Since you do have that option, it may cost you a stroke.

Answer 2

The ground might be under repair.