This pdf is 12 pages long, 1 page front cover, 1 page SRD, leaving 10 pages of new content, so let#s take a look at it.
We have all seen it in different media: Be it comics, cinema, books or even real life: Motivations that drive us to the point of being driven, principles that can and will not be broken by the respective people and, while constraining, also provide for a tremendous boost in capabilities at the same time, enabling them to endure and draw strength from their particular idiosyncrasies. This is made especially evident in moments where conflicting values between hero and villain or pro-and antagonist collide.
Why is it, then, that these iconic moments happen not too often in RPGs? First of all, there is a disconnection between players and PCs - the first reaction in many an otherwise great round will be to do what benefits the group in contrast to what the character might usually do. While some rpg-groups (Thanks for all the great years, fellows!) manage to transcend the benefits of the group for an "authentic" character reaction, it always leaves a shallow taste, even when XP-rewards are handed out later. There just is no immediate benefit for "driven" characters that adhere to a principle or flaw.
30 character motivations sets out to change that. Being portrayed as 15 pairs of opposable concepts, their mechanics are simple: When conflicted/confronted with a situation that goes against the motivation, a special check of d20+Int or Wis-mod is rolled against a DC set by the DM (guidelines are provided, basic DC is 15) - when successful, the PC can reign in his/her/its urges and act contrary to them. Otherwise the motivation has to be acted out, though not necessarily in self-destructive ways. From loyalty to lustfulness, honorable characters and cruelty - the range covered in the short space is quite interesting and offers something for just about anyone. Each motivation also comes with objects, i.e. concrete triggers: If your family has been slaughtered by goblinoids, you might have your lust for vengeance triggered in the face of these creatures.
Mechanically, the bonuses are not to be trifled with - they offer a higher power-gain than a feat (e.g. Brave: Immune to shaken and frightened conditions, +4 against fear and despair effects and reroll a fear/despair-related save once per day), thus a GM wishing to implement the rules should definitely make sure that situations come up that trigger the motivation to the detriment of the character in order to balance the benefits. On the other hand, the system facilitates e.g. playing characters like a smart fighter or a headstrong rogue.
We also get a new feat that gives you a bonus on the check to reign in the motivation.
Layout is ok and adheres to the two-column standard. Editing is fine, too and the full-color artworks are also ok. The pdf is short, thus I won't detract a star from the rating due to the lack of bookmarks - at 10 pages the file is easily maneuverable. I should note that the sub-header of the book is "New Traits for Characters", which is kind of a misnomer - this system has nothing in common with the standard traits in PFRPG. That being said, to tackle the system on its own ground, it works, is concisely written and professionally presented. However, as always with systems like that, DM-and player-discretion is advised when using the system to prevent suicidal stunts and balance issues/too frequent character deaths. My only true points of criticism for the system are that a) the motivations and their benefits are not that balanced and that some grant significantly stronger bonuses than others. GM-discretion is advised; and b) we don't get more content - while 5 bucks is not expensive, it's at the upper range of the impulse-buy range. I hope that we'll see 30 more motivations in a future supplement - the concept does lend itself to expansion. My final verdict will thus be a straight 4 stars.