The movie American Splendor featured Shay's resataurant rather prominently - Harvey ate their often. As did I when I lived over that way, and occasionally, I'll still make the trip to outside of downtown for a good, greasy breakfast. Also good if you've been out all night and need to make a pitstop before you go home and crash.
This place is a dive - in the best sense of the word. On a typical Saturday morning, you'll see whole families, neighborhood regulars and lots of hungover people, all chowing down on good breakfasts. The ambiance is definitely in the people watching. Mismatched booths, wobbly tables and an honest to god round breakfast counter in the middle of the main dining area.
The service is fast, the food is good and cheap - what more do you need?