Definitely The Forsyte Saga (1960s version) - think my mind was forged in the heat of all that smouldering passion. (My parents used to chase me out of the room if I somehow managed to still be downstairs when it came on.)
Steptoe & Son. Caught a glimpse of an episode recently and was astonished at how powerful it still is.
Original Poldark was the proverbial emotional roller coaster.
The Singing Detective - as outstanding and revolutionary in the 20th c as I May Destroy You in the 21st c.
Have you all forgotten - or perhaps have never seen Ultraviolet. I can’t even find the words to describe it. Just extraordinary storytelling, and wonderful cast.
This Life.
Queer as Folk.
Star Trek; Deep Space Nine.
Over lockdown - My Brilliant Friend, absolutely excoriating.
Buffy.
Doctor Who, especially Steven Moffat’s epic Matt Smith era story arc.
Years and Years.
Last Tango / Happy Valley
LOD
GOT
Money Heist
The Wire, Detectorists, MadMen, Chernobyl, The Bear, Succession - total perfection.