I used to buy gems regularly. Then, I decided to stop for a while (partly due to the bugginess of the game, partly due to the blatantly obvious ways gree attempts to separate me from my money. With the health potions, I got so carried away, that I went out and bought mountains of gems for three of my games.

Without potions, there is much less temptation to spend at all. The excitement is not there.

Consider this. Action, Reaction....