> Feedback works when it is fairly instant, friendly and most of all fair.
Well said. I assume that by "friendly", you imply "constructive".
Also: "How to Offer Constructive Feedback & Recognition" [0] and "How to Give Effective Feedback" [1].
[0] http://www.usc.edu/programs/cwfl/assets/pdf/constructive_fee...
[1] http://www.unh.edu/hr/sites/unh.edu.hr/files/pdfs/tool-2.pdf