I first got the idea of Motivation cards after playing a game of In a Wicked Age that didn't quite pop. In a Wicked Age, a bit like Paranoia and The Mountain Witch before it, is very much driven by the characters having goals that they're avidly pursuing - goals that are incompatible with each other. A pregnant situation is created, and something's got to give. You don't need an adventure for the characters to go through - in fact, such a thing is just a distraction, because the characters have their own plans.
Unfortunately, it's easy to screw up the goal-setting - (IaWA calls them 'best interests') - and end up with a game where the players goals aren't all that incompatible. Worst case, each player has a goal that doesn't interact with any of the other players, and it's like each of them are playing their own little two-player game with the GM.
I also think there's a certain fear of pissing other players off when people sit down to play a game of In a Wicked Age. Maybe they're strangers, or maybe they're used to D&D where you're (usually) all supposed to cooperate towards a common goal ... they're just not that likely to get involved in, say, a love triangle, one of the staples of drama.
Since, IMO, the best interests are the most important part of In a Wicked Age - more important than the Oracles, the method it uses to randomly choose story elements, which tell you what the game is about, but won't necessarily drive play - it seemed to me we should have some kind of "Best Interest" Oracle.
Which is something like The Mountain Witch - where everyone draws a Dark Fate card, and that guides their play - but the players all know each other's fates. And it's something like Fiasco, where some needs get randomly generated and shared between the players.
So I posted this idea on Story Games, and they refined it. I was particularly excited about Jason Morningstar's Shab Al Hiri Roach mechanic, where the motivations go in a circle: everyone loves the character on their right and hates the character on their left. Why not do that with these Motivation cards, I thought: all the characters will have issues that involve the character on their right, and be involved with the issue of the character on their left.
Less flexible than In a Wicked Age, sure - but it'll create an untenable situation every time.
Since I came up with the idea, I've been watching shows, movies, and reading books - and always asking myself, "What is this character's motivation? What is this character's motivation?" And trying to make sure that whatever it was, it could be expressed by one of the That's Drama Motivation cards.
Turns out there usually is not a lot of variety in motivations. Love and revenge are the most common. I ran out of ideas after eighteen cards, and since then haven't seen a motivation where I said, "Oh, I need to put that in the game."
That said, there are some 'tricky motivations' that are hard to game - any motivation about self-actualization or self-realization, for example, like Bill Murray seeking enlightenment in The Razor's Edge.
To keep some flexibility, for that rpg veteran who likes more control over their character's ambition, I added wild cards: invent your own motivation, as long as it involves the character on your right. Because I thought vets would want it. Interestingly, in playtesting, I've only seen a wild card used once. Some have suggested I take them out. I'm left them in, for now, because I don't see how they hurt anything. But it's a neat data point - it makes me feel like I'm really onto something with these motivation cards that seem constraining at first but really just let people express themselves.