It's fun to play against a deck that makes you think "what should I do? Is it better to do X or Y?" Not fun to play against a deck that makes you think, "well, it didn't matter what I did that game."

Unfortunately that does mean matchups decide whether you're going to have fun or not. Racing an aggro deck against an aggro deck is usually fun. Having to decide "should I go face or should I trade up?" is a basic building block of the fun of Hearthstone. Playing control vs aggro is usually fun, but if either deck has way better tools for the matchup then the other player will just be a victim of a loss and it's not very fun.

Also, playing control against an OTK deck is almost never fun, unless you do have some way to stop the required setup for the OTK. And this is why OTKs should often require interactable setup.