And one from my mid western grandmother to describe a project or job that’s really going well - “We’re really cooking with Crisco, now!!!”
I just heard someone say this at the grocery store today and immediately thought of this thread. 
My FIL used to say, “We’re cooking with gas!”
My MIL says, “Well that’s different.” She said it about D’s name when she was born…
I’ve always heard “We’re cooking with gas now.”
My grandmother used to say " If it suits you, it suits me." if she wasn’t overly fond of something. It seemed to be the 60s equivalent to “whatever”.
I think that this is probably a translation from another language–my wife’s family used to say this as well, and I think it was because that was how you say it in Slovak.
Hearing about “frappes” in Massachusetts reminded me of another one–a “spa” is a local convenience store (what you might call a “bodega” in New York these days).
I would like to note here, that catty-corner means something different from cattywompus. At least where I grew up, catty-corner meant located diagonally from something else (i.e., her house is catty-corner from the filling station"), while cattywompus means disordered or “out of true.”
I’ve always heard kitty-corner instead of catty-corner, still meaning diagonally across.
Cattywonker means all out of skew. When the tornado hit a building on my property, it knocked it all cattywonker. The studs and sheathing were all twisted off kilter beyond repair. The chimney and roof blew off. Maybe cattywonker is the same as cattywompus; I just don’t know “cattywompus” just cattywonker. I believe cattywonker does have a sense of twisted or skewed physically from the norm.
I only lived in the Boston area for 8 years, but my parents lived there more than 35. I can translate.
dungarees=jeans
chinos=khakis (although it is pronounced a lot like car keys - ca kees)
jimmies=ice cream toppings, free at Friendly’s
tonic= soda, like gingerale, orange
seesaw=teeter totter
lollipop=sucker
pocketbook (or pockabook)=purse
package store=liquor store
carriage, buggie,(in a pinch, wagon) = something you put either groceries or babies in and push around
half past = a time of the day that contains :30 (7:30, 10:30)
grinders=a sandwich, most often hot like meatballs
We moved to the midwest when I was almost 8. We spoke an entirely different language at home. My daughter, adopted from China, used to be so frustrated that there were 2 words for everything at Nana’s house - why sofa and couch? Why soda and tonic? Why frappe and shake? She was having enough trouble learning one set of words and thought it was really mean of us to have two words for almost everything. Now she has a boy friend from NJ and has to learn about going ‘down the shore’ instead of to the beach. Life isn’t fair.
In Singapore English (Singlish) they would say ‘please on the light’ and ‘please off the light’, omitting the word ‘switch’.
I don’t see chinos, dungarees, jeans, seesaw, lollipop, pocketbook, carriage/buggy or half past as being “Boston expressions” at all. I never set foot in Boston til my mid twenties and used all of those expressions growing up in Phila and certainly have heard/used them in the Midwest. Only package store and grinder strike me as Boston-specific, kind of like tonic or frappe or wicked.
One difference I did note in moving to the Midwest was that we would say “a quarter of 1” or “a quarter to 1” (for 12:45) and in the Midwest they said “a quarter til 1.”
I think of sucker as the colloquialism for lollipop.
And sucker can mean a lot of things - lollipop, leech, gullible person…
I never used package store (although I remember it as “packie store”), or tonic or frappe. I will confess to wicked, though. Ya gotta admit, “wicked” is just a good word. It’s deliciously elaborate 
My ohio MIL pronounces “wash” (in my mind, “wahsh”) as “warsh”. Like “warsh” the clothes. I love the phonetic nuances of speech.
@MotherOfDragons - My born and raised in St. Louis Dad also says “warsh” for wash. And my central Missouri born and raised Mom says “quater” when she means quarter. And then gets annoyed when we correct her… 
I have rarely heard this in Boston - I’ve mostly heard it being referred to as a “sub.”
Or more commonly, packie
Some other Boston vocab:
Wiffle - crew cut/buzz cut
Blinkers - Car directional signals (or hazard lights, depending on context)
Bubbler - Water fountain
Bulkie - Kaiser roll
Uey - U-Turn (e.g Bang a uey at the light.)
Supper - Dinner
Statie - State Trooper
And that’s even before getting into geographic terms (e.g. Southie, Dot Ave, JP, P-Town)
I heard grinder a lot in Connecticut. It always sounded weird to me.
Words I have gotten grief from over the years -
Squirrel - one syllable squirl
Drawer - again one syllable, draw
On - I turn things awn
Or so I’ve been told.
That said, my grandmother used a terlet (toilet), so I feel good about my pronunciations.
@oldbrookie Was your grandmother Edith Bunker?
If we are chatting now about accents or dialects, my freshman roommate was from BAAAAAAAston. If we were going out, we were going to a “party”. To her it was a “paawty”. To me that’s the same as the “terlet”.
God no! Came to this country when she was 16 all by herself. Hardest working, greatest lady who ever lived. Her son was on the team who performed the first heart transplant. Amazing woman.