What Are the Limitations of Mana?

Mana is really nice in that it gives us control. As i make a one drop, you like, a one drop is designed to be played early. Not that it can't be played later,. coking, drawt later, butit gives us te the designers of the game, some ability to have some say about when and how things get used. Another thing i should mention is when you talk about costs, there are sort of what i'll call main costs and what i'll calls additional costs.