Anthony's problem was that he thought this was incredibly funny, and that his dad instincts kick in even when a kid tries to rob him. Especially when a kid tries to rob him. 

"Yeah, okay," he nodded. He has finally broken the spirit of this child. He is victorious. "I don't think you're very suited for this whole 'robbing people' thing, though—I would know. You're not very intimidating or convincing, really. And honestly, I feel like getting yourself a knife that isn't a kitchen knife would be a good call." If this kid's going to rob people then at least he should be good at it.