Why didn't the bank authorize my ATM withdrawal?

Alot of ATMS will not dispense anyhthing over $100.00 basically for your own protection. ATMs are not safe and don't want to take the chance of one of their customers getting axed while withdrawing that large amount. Why not just go into the bank up to the teller. You would have to do multiple transactions at least 10, $100.00 each time. It would cost you more to do that than just go in into the bank. Or they could of had a glitch in the computers.