Take a peep at Andrey "Reynad" Yanyuk's Twitch chat, and you're fairly likely to find at least a few PJSalt shakers in there (used in the chat to note when someone's acting upset, if you're unfamiliar with Twitch-speak.) But while Yanyuk's reputation as a sore loser might precede him, there's no doubting that players can learn a lot from his stream. The founder of esports organization Tempo Storm perhaps isn't the best teacher on this list, but he's got some of the best insights about the design and metagame aspects of Hearthstone. No matter how bitter he might sound at times, the truth is that he's often right when sharing his instincts. When he analyzes a card buff or nerf, you should take what he says to heart.
Whether you like him or not, there's something to be said for Reynad's particular brand of saltiness: when he loses due to a topdeck or coin flip, we all feel for him. Because really, what Hearthstone player hasn't done a Reynad eye-roll in the wake of a bad beat?