Around June of 2011, I lost access to several channels I used to get, including A&E, BBC America, Cartoon Network, the CW, Disney Channel, Disney XD, FX, Nickelodeon, Nicktoons, Syfy, TNT, and USA. Some of these channels' shows I've been able to watch online since then, even if I had to wait between eight days and a month after an episode airs. However, some of them I haven't been able to watch online. So there are some newer series I've never seen at all (see links at the top of the page), but on this page, I'll list shows I used to watch, but have fallen behind on. Shows I very much hope to catch up on, someday. (There are also some shows I managed to watch online for at least one season since 2011, but later began missing, for various reasons.)
Adventure Time, Cartoon Network
The Amazing World of Gumball, Cartoon Network
Aqua Something You Know Whatever, Cartoon Network (adult swim)
The Avengers: Earth's Mightiest Heroes, Disney XD
Batman: The Brave and the Bold, Cartoon Network
Being Human, BBC America
Ben 10: Ultimate Alien, Cartoon Network
Bleach, Cartoon Network (adult swim)
Doctor Who, BBC America
Eagleheart, Cartoon Network (adult swim)
Falling Skies, TNT
Fullmetal Alchemist: Brotherhood, Cartoon Network (adult swim)
Generator Rex, Cartoon Network
Iron Man: Armored Adventures, Nicktoons
Mary Shelley's Frankenhole, Cartoon Network (adult swim)
Metalocalypse, Cartoon Network (adult swim)
My Babysitter's a Vampire, Disney Channel
Phineas & Ferb, Disney Channel
Pokemon, Cartoon Network
Star Wars: The Clone Wars, Cartoon Network/Netflix
The Troop, Nickelodeon
The Venture Bros., Cartoon Network (adult swim)
Young Justice, Cartoon Network
Zeke and Luther, Disney XD
Arrested Development is a special case. I had seen the first three seasons (2003-06) on TV, but the fourth season was on Netflix, which I never had access to.
In the spring, I was going to watch Bates Motel on A&E's website, as I had with season 1, but episodes for season 2 were locked, so I've missed it since then.
Also in the spring, I was going to watch Warehouse 13 on Hulu, as I had seasons 3-4, but the season five episodes were locked.
In the fall, I was going to stop watching several shows I normally watched on Hulu (particularly from the CW), because my internet had gotten too slow. But after a month or so, it got fast enough again, so I caught up on most of the shows I'd been missing since the new season started. However, I was too far behind on Reign, so I have missed season 2 onward.
In December, I was going to watch The Wrong Mans on Hulu, as I had season 1, but season 2's episodes were (mostly) locked.
In the spring, I was going to watch Salem on Hulu, as I had the first season, but the second season didn't appear on that site.
In the spring (I think), I was going to watch Moone Boy on Hulu, as I had the first two seasons, but season 3's episodes were locked.
In the spring, I was going to watch the webseries Deadbeat on Hulu, as I had the first season, but season 2's episodes were locked.
In the summer, I was going to watch Defiance on Hulu, as I had the first two seasons, but season 3's episodes were (mostly) locked.
In the fall, I was going to watch Manhattan on Hulu, as I had the first season, but season 2's episodes were locked.
In the fall, I was going to watch the webseries The Awesomes on Hulu, as I had the first two seasons, but season 3's episodes were (mostly) locked.
Actually, starting in the last week of December 2015, I have been missing the final season of Sailor Moon, after watching the first four seasons on Hulu. I saw the first few episodes of season 5, but then my internet got too slow to watch anything on Hulu, and it hasn't gotten any faster since then. This also means I've had to stop watching several CW shows that I had been watching on Hulu, most of which I was in the middle of the seasons of. (They were on winter break, but returned in January 2016, which is when I started missing them.) Those include The Flash (season 2), iZombie (season 2), Arrow (season 4), and Supernatural (season 11). I also have not been able to watch any of season 3 of The 100 (its season started in January). And I missed the last few episodes of NBC's Heroes Reborn. And... I'm not sure what else I may end up missing. (Some things I used to watch online because of scheduling conflicts, but I do get on TV, so I may be able to DVR them. I'm not sure yet.)