Is this satire? Surely you must know that many (most?) human beings don't conform into your presuppositions about value and the meaning of positive and negative, given that life isn't a spreadsheet.
The mathiness of it is, admittedly, a touch tongue in cheek. But the underlying philosophy stands: Despite there being as many different views on "What do I value" as there are people, it's hard to construct a value system where sitting on the couch isn't paying a significant opportunity cost, unless you axiomatically take sitting on the couch as the greatest good there is.