Talking about Art Laffer and his curve Jonathan Chait says this:
This is not merely a technical objection. It exposes a conceptual flaw underlying Laffer’s entire premise. People are not, in fact, utility-maximizing robots. They choose to work for reasons other than maximizing their incomes on the margin: habit, pride of craft, and so on.
Utility maximising does not mean revenue maximising. That’s why we use the different word, utility, because it does not mean revenue. Things like habit – because change is annoying and thus detracts from utility -, pride of craft – because boosts to the ego increase utility – and so on and on are parts of utility, the thing we claim is maximised.
People are utility maximising because the original observation and definition is that utility is the thing people maximise. Also, that utility ain’t the same as revenue.