The two questions in this little conversation are evidence of a broken KM culture.
It's the sort of conversation most of us have had at some time on our lives. In this conversation we can see evidence of a missed opportunity to share knowledge ("I could have told you...") which had negative consequences ("... it wouldn't work"). This is what we call the "Cost of Lost Knowledge", and the elimination of such consequences is the primary value that Knowledge Management will deliver.
Why was this opportunity to share missed?
Firstly there was no supply of knowledge ("Why didn't you tell me?"), and the knowledge manager exploring such a Lost Knowledge Incident would want to explore this lack of supply. Did the knowledge supplier not want to share? Did they not know how to share? Or did they not even know they were supposed to share?
Secondly, and perhaps more fundamentally, there was a lack of demand for knowledge ("Why didn't you ask me?"). Again, this needs to be explored - was the knowledge seeker unable, unwilling, or unaware?
If you know whay the transfer did not happen, then you can address the awareness, the willingness, and the mechanism, and ensure that the sort of conversation shown here never happens again.
If this conversation reminds you of your organisation, and you would like help sorting it out, give us a call. We can help.