One of the most crucial parts of character development in tabletop games occurs, at least chronologically, before the campaign begins. As a form of collaborative storytelling, every character should, at least barring extreme circumstances, have some background with connections, family, and a history. Unfortunately, many games and groups overlook this aspect of play, despite the fact that it can be simple and fun to implement.
First and foremost, I have never seen a game harmed by a character having a realistic background. That’s not to say that every background is good; I’ve seen a lot of players who try to use a background for unfair mechanical advantages or to direct the plot into becoming oriented around their character. However, should a player’s character gain an element of humanity, motivation, and depth from their background, it will create a massively more interesting dynamic in the group, and provide some elements to the plot that the GM won’t have to go back and personally create.
Equally important, however, is the fact that players who put background into their character are less likely to “misbehave”, participating in disruptive table behavior. Of course, to a certain degree this depends on the degree to which the Game Master participates as well; I’ve played in a game where the Game Master, despite his best intentions, didn’t come across as taking the game super seriously, and the players felt like the setting was shallow despite the many preparations he had made to craft the mechanical aspects of the game. Still, deeper characters have a larger investment for players, and they’ll be more likely to go along with the story and remain engaged than if they have shallow, meaningless characters.
However, it’s also important to note that roots mean that characters fit the setting better. When a character has a background, they will have certain things that other characters won’t; I’ve seen combat monsters turn into charismatic protectors in the course of a three-hour character creation binge as their player decides that they don’t just want to play the scariest guy in town and would rather play someone who has a purpose and background beyond making things dead.
I’m not going to go into too many details about growing roots here; for the most part it’s common sense. Shadowrunners may have buddies who are squatters or corporate wageslaves, traditional fantasy adventurers may be saving up coin to send home to repair the damage from the last battle with the dragon, or spacefarers may be looking for the lost secret of faster-than-light travel to go back to Earth and see what happened to it. All of these things add depth and meaning to a campaign without making the GM lift a finger.