Greasy spoon or dive?

So what is the difference (or what are the differences) between these?

I've been trying to figure this out lately and am not having much luck...there is a smallish diner near me (the Seneca Knolls Diner) which I am almost certain counts as a greasy spoon...not spotlessly clean, but great food.  Torn seating, but enough of it for people to relax/conversate without being crowded.

Also, they tell me that there is additional seating, though darned if I know where- it's not that big.

I know Doc's used to count as a dive....it was a Mess with a capital M.

Bah.  I need to go eat more and get back on track...

In the pipeline?

• Gem Diner
• Seneca Knolls Diner
• Thee Diner (in Cicero)
• That Little Diner (on Erie Blvd)
• Cottage Restaurant

The B'ville Diner I am still up in the air on...but will probably hit there at some point.  Suggestions in the comments are much obliged and certainly welcome.