If you had to choose between the 2015 ALCS against Kansas City and the 2016 ALCS against Cleveland, as Blue Jays fans which was more frustrating to watch since in the end Toronto ended up losing both series.
With Kansas City it was annoying just how many times they were able to comeback late in games, like when they were losing 6-2 against Houston in the 8th inning of Game 4 of the ALDS and in the 7th inning of Game 2 in the ALCS, although Goins and Bautista not catching that popup didn't help.
As we all know the Cleveland bullpen was un hittable when Miller and Allen came in, plus the Blue Jays bats going cold also did not help.
In the end I say 2016 was more frustrating because on paper Toronto should have defeated Cleveland and at least their offense showed up in 2015 against Kansas City.