"Oh man..this damn Priest killed both my early drops"
"Damn priest killed by 6/5"
"Lawl, 2 4 powers this turn, priest getting smashed"
"This Priest is so annoying, just dragging the game out with mini heals and picking off some minions"
"Oh well I won anyway, he had nothing left that was a threat"
"Silence owns Priests lol" -Note, I do not run the gimmicky inner fire deck
"Aww..priest MC'd my (random legendary), doesn't matter he's still dead to the horde of 4 power I still have on the board that he couldn't deal with"
In essence, Priest class probably annoys the most, but in the end lose a lot. I actually have to sometimes tell my friends to stop complaining so much when they win.
I'm not saying Priests are incapable of ranking up or are complete trash, but honestly, stop remembering all those annoying moments that a Priest can do and really try and recall your matches with Priests and how many times those "annoying OP cards" actually made you lose.
I'm going to guess not very often.