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If service with a smile results in a good tip, then Steak n' Shake waitress CeCe Bruce is smiling from ear to ear.

Bruce, a waitress for the past two years at a Steak n' Shake in Indianapolis, is $446 richer after a longtime customer left her a tip in that amount on a $5.97 order.

"My first reaction was, 'Miss Jo, I'm not taking your money,'" Bruce, 31, told ABCNews.com. "It was crazy."

The customer, identified only as Miss Jo, eats at her local Steak n' Shake at least once a week and was evidently feeling very generous when she came in for breakfast Wednesday morning.

"She asked me if she could leave me a ridiculously large tip, but I did not know that it was that large," said Bruce, who described Miss Jo as a middle-aged woman - "my angel."

"She didn't even give me time to tell her, 'Thank you,' or anything," Bruce said. "When I went back to get my manager, she took off out the door. I went outside and she said, 'You're going to take that money,' and drove off."

"I haven't had the time to even express my gratitude to her," she said.

What Bruce has had time to do is put the $446 tip to good use by paying her bills.

"I've already spent it," said Bruce, who, in addition to her full-time waitress job, is a full-time student at Martin University studying psychology.

She is also already back at work at Steak n' Shake, speaking to ABCNews.com in between serving customers.

As to her secret for delivering service good enough to warrant an approximately 7,000-percent tip, Bruce was humble in her own praise.

"I'm not exactly sure," she said. "I just try to have a nice personality. I do my job to the best of my ability every day."