When I'm not trying to rank up, I instantly concede against Priests. For example, when I'm just trying to knock out the daily quests, if I see a Priest, I just concede. Even the decks I have that can win against priests are soul crushing because it always goes to fatigue.
And that brings me to my main point, I concede very early in games. I've played enough to know when my position has become unwinnable. There are a LOT of people who will play to the very last card thinking that they can topdeck their way to a win but I've found that rarely happens. If I'm in a position where a single card can turn the tide and give me back the edge, I'll hang in there but as soon as I realize the game is not winnable, I concede. I really wish other people would do the same (especially those priests I actually play that insist on taking the games to fatigue when they simply cannot win). I'm sure the person on the other end thinks I'm rage quitting but, in fact, it's the exact opposite. I've calculated my odds, realize my position is not able to be salvaged so I concede to get into a new match as soon as possible.