"You know it becomes a problem when it becomes emotional, something you can't do without."

Studying casino and slot machine can be incredibly interesting. If you haven't readup on the wonders of the gambling business, I highly recommend you check out this Online Stanford Design Course, specifically focused on design's role in casinos.

The online course is splitup into the following chapters:

Tracing Technology and its Effects on Slot Machines
The Psychology of the Slot Machine
Analysis of Casino Design
Casinos and Economics
Social Implications
$pringfield: Gambling and Slot Machines in Popular Culture
Our Experience with an Online Slot Machine Simulator
The Slot Machine: Concluding Remarks

Very fun and interesting stuff.