Contrasting difficulties are like price decoys
When various pricing plans are introduced for a product or service, more often than not is not to get customers to go for the most expensive ones, but rather to make them more inclined to go with the middle ones. The relative cost contrast makes the middle options appear better options, in comparison. A similar perception modulation based on contrasting instances takes place in robotics. Additionally, introducing personal tasks with varying levels of difficulty might make it more attractive for the individual to engage in more challenging tasks than usual, due to their relative ease in comparison to the most challenging ones.