TV Shows:
Adventure Time and Regular Show- Was watching both pretty consistently up until around… spring 2014 I believe. At that point in time I kinda stopped keeping up with a bunch of shows I was watching due to the end of college approaching and I needed to concentrate more on that. Another show affected by this was Steven Universe, which at the time was mid way through season 1. I really let everything pile up, but I did finally catch up on Steven Universe by 2015. AT and RS? I dunno why I haven't caught up on either yet, I could easily catch up on both via KissCartoon. I guess chalk this up to me prioritizing other things first over catching up on certain specific cartoons (thankfully I still remember where I left off on both).
Doctor Who- I marathoned the entirety of the 9th, 10th, and 11th Doctor seasons leading up to the "50th Anniversary Special" in 2013 (trust me I would marathon the pre-9 stuff if it was convenient, but given all the "lost episodes" and the like it's not looking like an easy task), but once the 12th Doctor season began I had lost track of the airing schedule and just let episodes pile up so I could marathon them later. I've only seen the very first 12th Doctor episode, I need to catch up on the rest of what's aired so far.
Archer- I simply just never kept up with when season 7 would begin airing. It looks like the season has already ended so I should try and marathon it when I get the chance.
Movie series:
Marvel Cinematic Universe- How badly do I need to catch up on this? I haven't seen a single MCU movie since The Avengers in 2012. Yeah I'm THAT behind, and I don't know why I'm so behind either.
X-Men- This is more or less separate from the MCU anyway due to FOX still retaining the rights to X-Men and some related characters like Deadpool, so that's why I'm marking this separately. I saw First Class and really liked it, but I never got around to seeing Days of Future Past, The Wolverine, or Apocalypse. I have seen Deadpool but that's because it's not THAT heavily related to the X-Men films, meaning you can see it without watching an X-Men movie and still get what's going on.
James Bond- I never got around to seeing SPECTRE when it was in theaters and I've yet to even rent it on DVD.