I keep waiting for something good to happen, but it's a constant grind with little payoff. Most of the "rewards" are basically useless (upgrades to power ups I don't use), constant ads (even more with the latest update), and the good cars are for pay only (can't I get just one fast car with the gems I earned from hours and hours of watching your ads??). New tracks are few and far between, and each update is designed to stretch more ad time out of users without offering more value in return.