DISCLAIMER #2: I accidentally stopped watching after season 8, so this is technically incomplete.
So much of this show blurs together because there's SO MUCH going on all the time, and when you add in the fact that I binge-watched season 6 over the summer and probably skipped more scenes of boring things than usual, it's even worse. Oh yeah, did I mention the part where I have a tendency to skip over storylines that annoy me? So this is really more a ranking of the parts I liked best in each season.
Voice: QUIT STALLING.
Season 7: Pretty sure this was Peak Shipping Territory, as far as when I had the maximum number of ships and they were all at their best for the majority of the year. Like, it has been a straight upward trajectory for a long time. Also, this year had the musical episode!
Season 6: Owen/Cristina to infinity and beyond. Plus a bunch of adorable new doctors i.e. APRIL. And of course, that legendary finale. Just pure legend in my heart. I've personally dubbed it a TV trope, "Shooter Loose in the Hospital," to refer to when you put every single main character in various types of danger or panic/worry.
Season 5: Setting aside that episode which totally never happened (Owen obviously just appeared as an employee one day and needed no special introducing)...Derek/Meredith was on fire and Owen/Cristina was super hot. I learned all the wrong lessons about PTSD in this one. Also, whatever, I really liked Izzie/Ghost Denny.
Season 4: Poor maligned Nurse Rose: #1 thing I remember about this season. (I will go to my grave LOVING ROSE. And Derek/Rose). But I also have generally favorable memories about this season's scripts, which is the only year I remember strongly enjoying the cases more than relationships. Plus, this was the year Lexie arrived! And also Ava was still there, right?
Season 3: Ferry crash, Addison Largely Being Independently Awesome, Mystery Ava, and Burke's Sekrit Injury Cover-Up/the leadup to The Wedding That Wasn't were good! The arrival of McSleazy and an increased focus on Meredith's dumb family not so much.
Season 2: Addison entered my life as a Queen. That time when Derek and Meredith weren't sleeping together because their relationship was still gross and wrong was a refreshing change from season 1. Cristina's ectopic pregnancy was a real good series highlight to me. I do not recall anything else.
Season 8: Between Cristina having an abortion and Derek and Meredith adopting a random-ass baby, depriving me of pregnancy storylines, this was my FUCK IT, I'M ONLY HALF WATCHING EVERYTHING year. (even though if I judged by highlight scenes alone, it would go somewhere between 5 and 7)
Season 1: Honestly, I only remember it being such straight sleaze and awkward "look at these baby interns" footage that I never wanna go back to it. It is A Mystery as to how it ever hooked my college freshman self, in the days before my TV blog. (except probably it was a combination of the medical cases and the independent awesomeness of Bailey and Cristina)