This is along a similar vain to What happens when I cast a spell incorrectly? but only in that it created a further question.
At what point is it possible to decide that you don't want to cast a spell?
It's a very bad habit i know but i often find myself taping mana for a spell then thinking better of it. I've always just gone along with it after that, i followed through the action even if i see a better option but would it be right that i could change my mind and untap my land to carry out a different action?
What if i don't tap my land but simply drop a spell from my hand to the table without saying anything? Is the casting of that card implicit or would it be right that i could return the card to my hand?
Example - I have 3 cards in hand and 4 untaped land. I tap 3 land for a spell, then without saying anything or placing a card on the table i decide that really i want to cast a spell that only requires 1 land to be taped. Would i be allowed to untap either 2 and cast my 1 mana spell or all 3 land and start again?
Sorry that's more than one question! Thanks, 7's