Question about the movie 'Rounders'

[jwvdcw]

Sorry if this has been asked before.....

At the end scene, after Mike beats Teddy KGB, Grandma is visibly upset. He takes a chair and flips it upsidedown in anger. Why is he so mad? The way I understood it, was that he was still getting his $15,000, its just that Teddy had just lost a bunch of money. But Grandma didn't lose any money did he? He was still to get his money, which he was getting a great percentage of('I got a really sweet deal. Theres not a lot of faith in you', he said to Worm earlier). Moreover, Grandma kinda liked Mike, so he wouldn't really be any more loyal to KGB than to Mike. So why was he so upset?

Sorry if I'm overanalyzing things, but I've seen it a ton of times, so I'm starting to notice all the little things.