The absolute final nail in the coffin for me was the end of Wenger. He was the last link to the days when I really loved Arsenal/football and genuinely cared deeply about the team/sport.
It's a feeling that faded as I got older. Partly because I just got older and realised caring about a bunch of blokes in fancy PE kits running around a field wasn't really that important, but partly because I became conscious that many of the things I liked about it were beginning to fade away. As more and more players I cared about left and went away the less I felt attached to everything.
I've said it before, but by the end, and for the last few years before the end, I was more of a Wenger fan than an Arsenal fan. I will always support Arsenal, can't just stop caring completely. but I can't see myself ever being invested with them like I once was.
I think the last season I really cared about was the 2011/2012 one. Probably one of the worst seasons for Arsenal (up to that point anyway) since I had started being a fan objectively speaking, with a pretty iffy squad and loads of gaps, but I loved it and was so into it. Beating City 1-0 when Arteta belted in the winner from 30 yards late on, Henry making his comeback and scoring against Leeds, Van Persie being amazing, beating Spurs 4-2 after being 2-0 down. Gosh it was an exciting year.