That is a difficult question. It dependent on the mood I want to create, emotions I want to evoke, memories of who I shared it with and at what time in my life. That said I liked and watched House all the way through and am good to watch episodes again. There was large number of friends I watched it with shared in quotes and inside jokes.. same as Buffy, Scrubs and Serenity or rather Firefly even Dexter. (Big thing for Joss Whedon back then watched all his stuff) Those were all from a simpler time in my life. I was young carefree and the memories affiliated with them are linked.
I liked Mad Men but never completed it. The richness of the world etc, the modern take on a historical time. I loved Deadwood. The beauty and attention to detail. How quotable it was. The amazing dynamics of the actors. Deadwood leads me to Justified which wasn’t as great but Timothy Olyphant was gorgeous in it. I think that was his best role. He owned it.
True Dectective is brilliant. I never thought Matthew McConaughey could act until that role. I’m into Supernatural. But I always did have a thing for fantasy/sci fi.
There are so many more but I think those are the most memorable and rewatchable to me. Which is the ultimate test.