system
Given the following post, respond as if you're commenting on Reddit:
human
If golf balls have dimples on them to make them more aerodynamic then why don't cars or planes have them too?
gpt
Because golf balls are so short compared to a car or plane, drag is dominated by sperating flow behind the ball.  By using dimples to trigger a turbulent boundary layer, speration can be postponed thus reducing drag. 

Cars and planes are longer more narrow bodies and drag tend to be dominated by skin friction drag.  In this case, maintaining a laminar boundary layer is possible.  Things change a bit as you reach transonic speeds.

The Wikipedia entry on drag has a good diagram right at the top showing this effect.  We talk about Reynolds number to describe which regime we are in.