For those who do not play Hearthstone, I will explain too much.
Each day you get a new, random daily quest. You can have three. Also, each day you can discard one daily quest to replace it with a different random one.
I try to be efficient, and swap out quests that reward 40 gold for using specified heroes to obtain quests that can be obtained with any hero. That way every third day I can (hopefully) play a few games that fulfill requirements of two if not three quests.
Over the past few days I got lucky. Today I can play with any hero, and be working on fulfilling all three quests simultaneously.
Moreover, that central quest is the only daily quest for which games played by challenging a friend count. That is extra fun compared to playing against random opponents.