Also like in Duolingo, where you pay 2 "lingots" to place a double-or-nothing bet that you will practice every day for the next week. Most of the time I bet even though I know I'm likely to lose the bet, since it is slightly more likely I'll practice with a 'financial' incentive. Which is exactly what Uber wants to induce: early week optimism, then late week indentured servitude.