2004, 2009 and 2013 were depressing years in my books.
2004 because coming off an 86-win season in 2003, and with some youngsters like Wells, Hinske, Phelps, O-Dog as a core, I was excited heading into the 2004 season. Thought they would have built off that 2003 season but everything went wrong from the get go in 2004. Doc wasn't in Cy Young form and injured, bullpen sucked despite some additions in the offseason, it was Delgado's walk year as well and every Jays fan knew the team didn't have the money to re-sign him. Phelps ended up sucking even more and traded for Erik Crozier lol. Hinske was awful as well and never returned to his 2002 ROY form.
2009 because the Jays came off a solid 2008 season, but they lost AJ Burnett after he opted out, and the season already had a damper knowing that McGowan and Marcum were going to miss all of 2009 after getting injured during the 2008 season. It was Doc's last season in Toronto, and we kinda all knew he was going to be traded in the offseason. Their starting rotation in 2009 was awful after Doc. Wells was awful in 2009 and Rios ended up being traded that summer. Recall that was the season he was outside of the ROM and had that interaction/argument with a fan "Who gives a Fawk." It was cool to see Adam Lind and Aaron Hill have breakout years offensively.
2013 because AA made a bunch of big moves and it looked the Jays were ready to take that next level. Dickey was never in Cy Young form, they had injuries, Lawrie never amounted to anything, Josh Johnson was toast lol. Depressing season considering the high expectations after that busy offseason the Jays had and with guys like Bautista, EE already in the fold.