1. Avatar, The Last Airbender - My absolute favourite tv show. It just handles almost all the topics it takes on with grace and maturity and has some of the best written and developed characters of all time. Steven Universe is giving it a run for its money although that show has been spinning its wheels for a little while now sadly.
2. Survivor - Throw me on that Survivor and The Genius are both fantastic and the pinnacles to which all reality tv should aspire to be. I think that both shows are so interesting from even a game design perspective, and the intrigue/social manipulation plus my general love of board games make these two shows a no-brainer.
3. Firefly - Had to have a Sci-Fi entry here but also a 'serious' show. I don't really like a show unless there is at least a hint of comedy and Firefly nails that sweet spot of incredible drama intertwined with notes of comedy. I couldn't get through Breaking Bad because everyone was so despicable I couldn't bring myself to care about them, and other "serious" shows tend to just leave me staring blankly at a bunch of (imo) unrelatable characters. The old Star Trek series, Game Of Thrones, even Mr Robot all have these notes of comedy and levity with their drama and I love it.
4. Psych - A silly show about two best friends who solve crimes with and without the police. It's just got fantastic character dynamics, which on top of the characters being fun in their own right just makes for a great time. 8 seasons and the show pretty much just rides on its core aspects, and it's incredibly consistent. Proof of just how far good characters can take you. Scrubs, Brooklyn Nine-Nine, Parks and Rec all fall under this mold but I feel like Psych did it best.
5. One Punch Man - I enjoy a good anime but OPM is more than just an anime. It's a fully thought out and realised parody of an entire trope. I liken it to Angie Tribeca and Another Period where it takes this overdone formula and just gives it a completely new spin, but OPM is special in how it actually takes that comedy aspect and makes this really grounded and philosophical story. The Good Place is doing similar things with the sitcom trope as well.