The Tottenham Hotspur defender was reacting to his side's 1-0 defeat.
Sergio Aguero scored for the Manchester side at White Hart Lane as the visitors left with all three points despite a dominant performance from Spurs.
The north London side had their chances - plenty of them - and Dier lamented their inability to put them away.
The 21-year-old also made the frank admission that he should have scored with one of his headers and said he is disappointed with himself.
The Manchester City loss seemed to sum up Tottenham's season: good but not good enough.
.@ericdier: "I should've scored the header. I'm disappointed with myself. I should have scored." Interview on Spurs TV soon.— Tottenham Hotspur (@SpursOfficial) May 3, 2015
.@ericdier: "It's frustrating. We played well for majority. They had spells but we played well. We missed chances which is disappointing."— Tottenham Hotspur (@SpursOfficial) May 3, 2015
Tottenham now sit three points behind fifth-placed Liverpool having played the same number of games as them. That also means the north London side remain a good seven points off the Champions League places and just a point above seventh-placed Southampton.
Harry Kane was kept quiet against Manchester City, while Erik Lamela shone for the hosts. It was one poor moment once again that decided the match, though, as Spurs let City catch them on the break. Aguero was on hand to punish them...