system of ascending precedents

a sequence of events wherein each event sets a new, higher standard that will act as a precedent for all subsequent events.
-As far as I know, this phrase has never been coined or defined before.

Bob tells funny stories and does spontaneous imitations at work. each one is a little funnier than the one before. his co-worker's expectations track with his performance so that now he has to maintain the gradient of improvement every time he opens his mouth or, - and this is the key- they will respond as if it was less funny than it really is. He has trapped himself in a system of ascending precedents.