when you make a commitment to me, i expect you to follow through and deliver what you had promised me. if, for some reason, you cannot do whatever it is that you promised me that you would do, i would expect you to tell me that you were unable to do it. what i would not expect from you is not hearing anything from you and to be left wondering what the hell happened.
it is probably the biggest professional pet peeve i have when someone fails to get deliverables to me AND doesn’t say anything to me about it. it is not my job to check to see why you couldn’t do something that you promised me you would do!