Don't know about "classic". But diners used to be my weekly jaunt here in South Bay for almost a decade. Not any more because with age you realize the quantity is too much and my drive to work changed (WFH). There's something special about going to your regular place, seeing the same servers, and them knowing your order before you say it. Probably the same in dinner restaurants but we don't repeat restaurants as often whereas the breakfast / lunch diner was weekly so very familiar (to both sides). Tried to switch places a couple of times just for experience but it never felt the same ... but you can make it work.

When I lived in NJ over 20 years ago, I'd stop by a random diner on the turnpike and order 2 sunny side up and a cup of coffee. Or a Greek place mid-town, a sloppy gyro. It wasn't ambrosia, but it was "perfectly cromulent" and the gritty surroundings added to the taste. I'd do the same in Brooklyn under a random industrial street in Bensonhurst or Sheepshead Bay. That era is just gone. I don't remember seeing an avocado on the menu back then.

>...the quantity is too much...

Leftovers for a later meal. Unless there is something about work involved and not having a place to put the leftovers in the fridge.

Thanks I have thought about that, but somehow it does not work with me. Fresh food is something else (and my assumption is the food is fresh, even if it is just heating/grilling)

which one(s) in South Bay? any recommendations?

My favorite is Holders Country Inn. I used to go to the one in Cupertino before it burnt down. They moved, this was on Deanza long time back, and the one on Wolfe does not have the same old diner feeling, it is for the next gen :) Now I go to the one on Saratoga. And while I do not go as often to other places, I have been to and liked Hobees, then there is one Joe's near Half Moon Bay. We go there as a family when we hike at Cowell Purisima trail nearby. And while I am rambling about places to eat, a recent non-diner discovery has been El Caminito on El Camino Real.

Thanks, haven’t been to a diner in ages but have been meaning to go try out for old time time’s sake.

Used to go to Peppermill in Santa Clara, and Dennys many years ago.

Thanks for suggesting El Caminito, looks good. Our usual Mexican for many years has been La Milpa in Milpitas, haven’t found a good equivalent yet.

I wouldn't call it a diner but if you like these other places you might like Los Gatos Cafe

Lol thanks I will check it out, and I guess I was using the word diner way too loose - if it serves burgers, eggs and coffee, it hit my benchmark.

I used to love Alice's Restaurant in 2014-2019, but moved away, so idk what it's like today.

Not OP but I'd recommend the Peninsula Fountain Grill in Palo Alto. Peter's Cafe isn't bad either if you've got time to kill near the Millbrae CalTrain station.