My main job as part of Rideau View Golf Club's Turf Team is to cut the new hole positions each day. Unfortunately when I walk the greens of Rideau View I spend a good deal of time repairing ball marks - also called pitch marks - These are those little or sometimes larger depressions, or craters, made when a golfer impacts the green with his/her ball generally after hitting an iron shot.
When properly repaired you have a nice smooth-putting surface as well as a healthy green. When not done properly or not done at all (shame on you that don't) it can take up to twice as long for the green to heal.
So try and repair your ball marks. When you arrive on the green revel in the fact you hit the green. Repair your ball mark and at least one other one and the green will not only be better to putt on it's proper golf etiquette right?
Even though I do find him quite annoying sometimes Michael Breed from the Golf Channel has a good video on:
The Right Way To Fix Ball Marks
Be also sure to check out the GCSAA on repairing ball marks.