I generally believe that comments should be about “why is this code doing this” instead of “what is this code doing” because if you feel you need comments to explain what your code is doing, it could probably be refactored to be more readable and/or intention revealing.
One exception that I’ve often made is for recursive calls. I generally write a comment indicating that the method is about to call itself and why. This may be left over from my first CS class at the University where I had some kind of mental block around recursion, I don’t know.
So, I was delighted to see ReSharper give a little visual indication of a recursive call in the margin.
This useful when doing recursion on purpose (this example was using reflection to populate test data into properties, I would recurse when a property was a complex type), but it’s even more useful if you do recursion on accident, as in this public property returning itself below.