Over the Thanksgiving Week, Wizards of the Coast dropped Xanathar's Guide to Everything. This has been a well hyped book, and for good reason. Along with a slew of GMing tools that the book holds, it has expanded class options for PCs, clarifications and updates for older rules, and other options as well. However, my favorite part of the book are the groups of questions designed to help players flesh out their characters.
When making 5E, the designers said they wished to return D&D to its routes as a story telling game as much as anything. They did this in part with the three pillars of adventure: combat, exploration, social interaction. However, they've also done this with questions designed to help players play their characters - and not just an avatar of themselves at the table. With Xanathar's they expand this.
Each class has three questions specific to the class, and at least one is designed to bring in conflict for the character. A cleric, for example, is asked how they are imperfect in their devotion - what emotion do they feel that their god or teachings would frown upon. A Paladin is asked what would tempt them off the path they have chosen. A Bard is asked what their greatest embarassment was.
These questions are important because in answering the question you have to come at the character from an angle that most don't - the aspect of how your character has failed, or could fail as the game goes on. In a sense you're arming the GM with a tool to use against you, and so many games train players to not do that that...it's kind of sad.
Other characters are more simple, but I love them too because they help explain the character. Tables and questions about family life (where you only have a 5% chance to not have known your parents!) Questions about your siblings. Questions about what made you become whatever your background is. Questions about what made you become the class you chose. It's not enough to just want to be a Drow, Sailor, Warlock because that's what you want to play. To make the character you need to know why these things happened, and once you know why they happened you have that part of the character made - for good or for ill.
Obviously they're optional, and not every GM is going to need them. Still, it's great to see the questions there. If only as a means of helping people make characters that will stand out beyond just being a sheet of paper with a race, a background, a class, and some stats on it.