Discipline

So maybe this is a bit ironic of a post to follow my Thankful post, but today was a very frustrating day. My eldest son, now five, drove me nuts at the doctor's office. He was well-behaved until he got frustrated with the iPad. He couldn't beat a level in Mega Jump so he banged it on his forehead in frustration. While I can appreciate his frustration, he needs to find a better outlet for it. I took the iPad away and made him go back to reading magazines in the waiting room. He then proceeded for the next FIFTEEN minutes to ask for it back. In his most annoying whiny voice. Complete with big crocodile tears. Our conversation went something like this:

D: I won't do it again. Can I please play it again?
Me: No. What you did was unacceptable. You cannot play it now.
D: I'm sorry. Can I play it now?
Me: Thanks for the apology. But you're still not playing it. The answer is no.
D: But I waaaaaaaaaaant to play it. I wannnnnnt to. Pleassssssse.
Me: The answer is going to stay no. Quit asking.
D: I wannnnnnnt to play. I wannnnnnnnt the iPad. I won't do it again. (repeat ad nauseum)

I tried ignoring his requests, after asking him to stop asking. I took away tv time, computer time, and told him he was going to take a nap as soon as we got home. I ran out of things to take away. I was very frustrated with his lack of listening. I don't go back on my word. He can earn back privileges for good behavior, but it has to be consistently good behavior out of the goodness of his heart, and not for the sake of earning privileges back. I guess this is what I'm doing wrong. Because the kid just won't take no for an answer. He badgers me until I get so frustrated that I end up just as upset as he is. How do you stop your children from badgering you when you give an answer?