It's about finding a good balance. Too difficult and people give up. Too easy and people don't invest into the product. I think a similar thing applies to free

It's about finding a good balance. Too difficult and people give up. Too easy and people don't invest into the product. I think a similar thing applies to free vs paid. Some times paid is better because free can be treated as cheap or with little value. See also http://firstround.com/review/How-Lumosity-Spiked-Active-Users-10-with-Complexity-Not-Simplicity/ http://firstround.com/review/How-Lumosity-Spiked-Active-User...