Magic: The Gathering has many exciting cards and some decidedly unexciting ones.
I contend that the least exciting card currently in Standard is “Authority of the Consuls.”
But being unexciting isn't inherently bad. It's a powerful defensive card used “as a sideboard” against aggro decks.
The attacking side adjusts their deck strategy from game two onward, factoring in its potential appearance. This is a genuinely exciting approach.

The problem lies in Arena's environment, where this card sees four copies in the main deck.
As you know, color quests refresh daily, requiring you to cast a specified color's spells 20+ times.
The most efficient way to achieve this is with a monocolor deck packed with 1- and 2-cost spells.
Not only can you rapidly progress the quest in a single turn, but “Authority of the Consuls” also has the effect of “disillusioning your opponent and forcing them to leave the match = earning quest wins.”
When a color quest involving white appears, you should use a white mono-color gain deck featuring this card. It's hard to imagine anyone actually enjoying playing it, but it can't be helped.

Despite only being able to stock three quests, maintaining a wide variety holds little significance.
If a color quest is still necessary, it should be “Play spells of all colors (750)”.

Other possibilities, like “Add x cards to your hand” or “Play for x turns”, should also be considered.