Is this why prices are sticky?:
Sticky prices and behavioural indifference curves, by John Komlos, Vox EU: Many quantities fail to respond smoothly to price changes. This column stresses that the ‘endowment effect’ – a well-known behavioral economics concept – implies kinks in indifference curves at the current consumption bundle price. Such kinks may account for the stickiness of prices, wages, and interest rates.