Don't confuse "interesting" with "fun"

In a card game, any one, there is a concept called "card advantage". In Magic that means that you have more resources than your opponent, you have more spells and cards to play under different scenarios. There are many ways to achieve that. The most basic form is to draw cards faster than your opponent. Or the opposite, to make them lose cards by means of discard effects. The idea behind it is that you are closer to the victory by having more spells at your disposal. It's a turn based game and every player goes through the same steps and phases. A player has the advantage by also having to play more cards and doing more actions per turn than their opponent.

In the set Odyssey Mark had the idea of playing around the concept of card advantage and force the players to discard to gain advantage. The idea itself is counter-intuitive. Every player wants to have cards in their hands and keep them for later. It may seem interesting to discard as a mean to win, but is it fun to do so? There was a mechanic in that set called "threshold" that triggered with seven or more cards in the player's graveyard. See both cards above. If you have both why would you activate the left one multiple times when "first strike" doesn't stack up? The card on the right can gain +7/+7 earlier in the game if the player discards multiple cards with the aid of cards such as the one on the left. The synergy is there but players didn't like it.

The lesson here is that the idea might be interesting on paper and play with the player's logical thinking. Or an idea can be fun and play with the player's emotions. In game this shows up when the player resorts to logic to build a strategy. While the game itself plays with the player's emotions because the player is going to feel happiness, sadness, nervous, fear, etc during a game. Mark cites that scientists that study how a person takes a decision notice that the decisions are greatly influenced by emotions, even more than they are by rational thinking. A card can be more rational or more emotional, both ways are possible and valid. However, when thinking about the game, cards that touch the emotional side have more value because the player wants to have fun and not have the fun spoiled by overcomplicated mechanics or things that are purely rational.

How can all that affect level design? A game, in overall, needs to be fun over everything else. After all that's the purpose of a game, to entertain. In here there is a matter of challenge and difficulty. If a game is excessively hard, it loses its fun value. Let's take a look at the Rubik's Cube. It's a puzzle where each side of the cube is a 3 x 3 grid. There are larger versions with larger grids on each side. Much harder to solve. Guess which size is the most popular one? The smaller, the classic one.

Mark's 12th lesson is about being careful to not design because you want to prove something. Let us ask: When Mark made the mechanic "threshold", was he trying to prove that he could make something cool? I'd argue that yes, he was being a bit of rebel in attempting to find new ways to play magic. Now have I ever done what Mark has? Yes. There were some levels in which I thought that something was interesting, without thinking on whether it was interesting just for me or the players. To give a practical example: suppose I make a Capture The Flag map for some game and I ask myself "Would it be interesting if the map has low gravity and/or has 10 paths going in and out each team's base?". I build it and then say "let's see how it plays". It may appear interesting at first, but I'm not all players. Are they going to have fun with it? Even if some players find my idea as interesting as I did, if they aren't the majority my map is going to fail.

Now, thinking on the opposite direction, can something be fun while at same time seemingly be stupid? That's something that's part of the human nature, I'd say. People do stupid things and have fun with them. To give an example I'd mention some sports which are risky such as bungee jump. If you look at it from the rational perspective you could very well ask "Why do people jump? They can die doing it". Yes, they can die, but at the same time it's the same rational thinking that can prevent deaths from happening by doing it according to all safety measures. People do it because they seek strong emotions. Magic's very nature is rooted in emotions and players do stupid things and have fun with it. How often in computer games players do stupid things, be it willingly or not, and laugh? All the time.

If I were to complement Mark's lesson I'd add that there is a clearly a matter of ego in all that, because what we think it's interesting or fun for us may not be for someone else.